697 results about "Metabolic pathway" patented technology

Disclosed is a system for detecting whether the breast cancer is benign or malignant based on multiple modalities, which comprises: an ultrasonomics model configured to extract breast tumor position information and breast tumor morphological features on the basis of an acquired grayscale breast ultrasound image, perform global interactive fusion on the breast tumor position information and breast tumor morphological feature information, and convert a Transformer encoder-based feature output into an output vector of the corresponding classification dimensions by means of a fully connected layer; a metabonomics model configured to obtain a metabolic fingerprint spectrogram and analyze the metabolic fingerprint spectrogram on the basis of a metabolic database and a predetermined significantly differential metabolite to obtain abnormal metabolic pathways, signal transduction pathways, and related biochemical reactions associated with breast cancer malignancy; and a detection module configured to perform joint modeling, based on the breast tumor position information, the breast tumor morphological features, and a peak value of the significantly differential metabolite of the breast cancer malignancy, to output a prediction result about whether the breast cancer is benign or malignant.

The invention relates to the technical field of genetic engineering, and particularly discloses a genetic engineering bacterium for producing melanin as well as a construction method and application of the genetic engineering bacterium. According to the application, the yield of the melanin can be effectively increased by modifying a metabolic pathway of the genetically engineered bacterium, and the yield of the melanin reaches 6.2 g / L and 18.5 g / L respectively through shake-flask culture and 5L fermentation tank culture. Compared with the prior art, the yield of melanin produced by the genetically engineered bacterium is improved by 30% at the shake flask fermentation level, the fermentation yield of a fermentation tank is improved by 4.3 times, in addition, expensive tyrosine is changed into glucose as a fermentation precursor substance, the production cost is greatly reduced, and an efficient and feasible solution is provided for large-scale production of melanin.

The invention discloses a gene and a protein for adjusting tobacco polyphenol aroma substances and application of the gene and the protein. The gene is a tobacco NtMYB28 gene, and the CDS sequence of the tobacco NtMYB28 gene is as shown in SEQ ID No. 1. The invention further discloses application of the tobacco NtMYB28 gene in regulating the content of endogenous polyphenol substances in tobacco and regulating and controlling the metabolic pathway of phenylpropane in tobacco. The key gene NtMYB28 capable of simply and effectively adjusting the content of polyphenol substances in tobacco and the metabolic pathway of phenylpropane is found, and the gene can be applied to efficient cultivation of new high-aroma tobacco materials and development and utilization of new high-value functional tobacco germplasm.

The invention is applicable to the technical field of bioengineering, and provides a coding gene for enhancing iron deficiency stress tolerance of plants and application. According to the soybean GmMYB14 transcription factor disclosed by the invention, the problem that the growth of soybeans is limited in an iron-deficient environment, particularly calcareous soil and soda saline alkali soil, is solved by excavating and applying the encoding gene (the nucleotide sequence is shown as SEQ ID No.1) of the soybean GmMYB14 transcription factor. Experiments prove that after the gene is over-expressed in arabidopsis thaliana and soybean, the tolerance of plants to iron deficiency stress can be remarkably enhanced. The invention provides a key gene resource for molecular breeding: the GmMYB14 effectively promotes the absorption and utilization of plants on iron by regulating and controlling the metabolic pathway of phenylpropane, not only can improve the planting adaptability of soybeans in low-iron soil, but also can improve the yield and quality of the soybeans, provides powerful technical support for enlarging the planting area of the soybeans in iron-deficient soil regions, and has a wide application prospect. The method is of great significance in relieving insufficient soybean productivity in China and improving the self-sufficiency rate.

The invention relates to the technical field of teasel breeding, and discloses a teasel germplasm resource multi-character collaborative screening breeding method, which comprises the following steps: multi-omics data acquisition: extracting teasel germplasm leaf DNA (deoxyribonucleic acid), and capturing exon regions of disease resistance and metabolism related genes by adopting a targeted sequencing technology to obtain an SNP (single nucleotide polymorphism) marker matrix; the method comprises the following steps: collecting root extracts, detecting medicinal components through ultra-high performance liquid chromatography-mass spectrometry, and constructing a metabolite abundance matrix; measuring phenotype data of plant height, root length, root weight, root rot morbidity and survival rate under drought stress; key site and metabolite correlation analysis: constructing a Bayesian network containing SNP markers, metabolite and phenotypes by using a graph database, and carrying out cross validation through a leave-one-out method. The dipsacus asper germplasm resource multi-character collaborative screening breeding method aims at solving the problem that a traditional breeding method lacks systematic integration analysis of genomes and metabolic pathways in dipsacus asper multi-character collaborative improvement.

The invention discloses a construction method of a soil microorganism nitrogen metabolism function prediction model, and relates to the technical field of environmental microbiology and agricultural information, and the method comprises the following steps: S1, constructing a spatial-temporal heterogeneity representation engine, and dynamically decoupling a multi-level gradient of a soil environment through an adaptive spatial-temporal mesh generation algorithm; according to the construction method of the soil microorganism nitrogen metabolism function prediction model, the adaptive capacity of the soil microorganism nitrogen metabolism function prediction model in a complex environment is improved, and multi-level environment gradient dynamic analysis from a centimeter-level rhizosphere microdomain to a kilometer-level landscape scale is realized; the problem of cross-scale feature fusion caused by temporal-spatial resolution mismatch of a traditional model is solved, the simplified hypothesis of a traditional statistical model on the synergistic-antagonistic relationship of microbial functional genes is broken through, a dynamic coupling mechanism of a nitrogen metabolism path under environmental disturbance is accurately quantified, and the prediction error is reduced compared with the prior art.

The invention relates to the technical field of collaborative prediction, in particular to a plant polygene stress resistance collaborative prediction method and system based on a federal map neural network. The method comprises the following steps: modeling a multilayer heterogeneous graph according to acquired plant genome data; constructing a dynamic graph neural network model based on time sequence perception; training a dynamic graph neural network model by using the multi-layer heterogeneous graph, and performing distributed privacy calculation on the multi-layer heterogeneous graph by using a federated graph neural network; generalization training is carried out on the small sample scene data based on multi-task learning and a cross-species migration mechanism; and obtaining a gene function prediction result. Through a multi-layer heterogeneous graph fusion technology and a dynamic graph neural network design of time sequence perception, multi-dimensional biological information such as gene regulation, protein interaction, metabolic pathways and stress response can be captured at the same time, and time sequence change characteristics of gene expression in the plant stress response process can be captured at the same time.

The invention provides a Baijiu brewing process simulation method and system, and the method comprises the steps: constructing a metabolic network model of a flavor synthesis path in a Baijiu brewing process, initializing the boundary condition of the metabolic quantity in the metabolic network model, and carrying out the flux balance constraint of the metabolic path of a target flavor substance according to the boundary condition, obtaining the constraint flux of the metabolic pathway of the target flavor substance, and further calculating the metabolic flux distribution of the target flavor substance in the white spirit brewing process; determining a reaction rate constant of each process parameter combination according to the concentration gradient characteristic and the spatial distribution characteristic of the concentration change information of the target flavor substance; and performing metabolism simulation on the brewing reaction of the target flavor substance according to the metabolic flow distribution and each reaction rate constant, outputting the metabolic quantity of the target flavor substance under each process parameter combination, and further screening the brewing process parameters of the target flavor substance. Based on the scheme, multi-parameter metabolism simulation of a flavor substance synthesis path in a white spirit brewing process can be realized.

The embodiment of the invention provides a recombinant pichia pastoris strain as well as a construction method and application thereof. The construction method comprises the following steps: by taking a pichia pastoris strain as a host strain, constructing a dual-synthesis path of phenylalanine ammonialyase and tyrosine ammonialyase in the host strain to obtain a first engineering strain; removing chorismic acid feedback inhibition of the first engineering strain based on metabolic engineering to obtain a second engineering strain; optimizing an aromatic amino acid synthesis route of the second engineering strain to obtain a third engineering strain; knocking out a branch metabolic pathway of the third engineering strain to obtain a fourth engineering strain; increasing precursor supply of the fourth engineering strain to obtain a recombinant pichia pastoris strain; according to the construction method provided by the embodiment of the invention, the synthesis path of p-coumaric acid can be systematically optimized, the recombinant pichia pastoris strain for efficiently producing p-coumaric acid by taking methanol as a carbon source is constructed, and compared with a host strain, the recombinant pichia pastoris strain has the advantage that the yield of p-coumaric acid is remarkably increased.

The invention relates to the technical field of microorganism monitoring, and particularly discloses a wetland microorganism activity monitoring method and system.The method comprises the steps that a plurality of first time sequence data sets of different layers and related to different wetland state parameters are obtained; analyzing and acquiring a parameter change mode of each layer according to the first time sequence data set; similarity matching is carried out based on the parameter change mode and a pre-constructed parameter correlation model library, so that microbial metabolism modes of different layers are determined; determining an activity evaluation mode of the microorganisms in the corresponding layer based on a microorganism metabolism mode; generating an activity evaluation result according to the activity evaluation mode and the first time sequence data set; according to the method, the biological action signal and the non-biological process signal are distinguished, the evaluation accuracy is improved, the activity evaluation mode corresponding to the metabolism mode is determined based on the identified metabolism mode, and the difference of evaluating the activity of microorganisms in different metabolism pathways by adopting one index is avoided.

The invention provides a yak healthy feeding optimization method and system based on machine learning. The yak healthy feeding optimization method comprises the steps of obtaining a basic data set; according to the basic data set, performing erucic acid metabolic pathway feature construction to obtain a feature set representing erucic acid mediated lipid metabolic pathway; according to the lipid metabolism path feature set, meat quality improvement effect quantification is carried out, and probability distribution of unsaturated fatty acid deposition efficiency is obtained; according to the probability distribution, feeding amount reverse deduction is carried out, and a high-erucic-acid rapeseed oil intake interval is obtained through calculation; health benefit balance is carried out according to a high-erucic acid rapeseed oil intake interval, and a stable feeding strategy is obtained; biological rationality verification is carried out according to a stable feeding strategy, the continuity of the mapping relation between the feeding amount and the meat quality index is analyzed based on the topological structure of the feature space, and a healthy yak feeding optimization scheme is obtained. The feeding precision, the meat quality improvement effect stability and the yak health guarantee level are improved.

An ultrasound-metabolic synergistic system for diagnosing SLN metastasis of breast cancer. A deep learning model based on grayscale ultrasound is constructed to predict SLN metastasis of breast cancer, and 9 grayscale deep features and 15 grayscale manual features associated with SLN metastasis are obtained. A matrix material based on two-dimensional material MXene / multi-walled carbon nanotubes improves the detection of small metabolic molecules in blood, and metabolomics analysis results show that this has certain potential in detecting SLN metastasis of breast cancer, while revealing metabolic pathways closely associated with metastasis, such as the glucose-alanine cycle and glycolysis, suggesting that alterations in relevant molecular pathways may underlie heterogeneous features in ultrasound radiomics. The combination of ultrasound omics and metabolomics further improves the diagnostic performance for SLN metastasis of breast cancer. Therefore, organic integration of the two serves the diagnosis of SLN metastasis of breast cancer, providing a new strategy and theoretical basis for the accurate diagnosis of SLN metastasis of breast cancer, and possesses practical clinical application values.

The invention relates to the technical field of plant breeding, and particularly discloses a metabonomics-based alfalfa stress resistance gene analysis function and a breeding method. The core of the method is that screening is carried out by combining a tissue culture technology with metabolic intervention; an alfalfa explant is inoculated into an induction culture medium containing a specific metabolic pathway regulator for metabolic intervention culture; then transferring the obtained callus to a verification culture medium containing the metabolism regulator and an abiotic adversity stress factor at the same time, and carrying out metabolism mark verification and screening; and finally regenerating the screened cell line into a complete plant. According to the method, metabolic pressure is actively applied to the cellular level, and dual verification screening is implemented, so that early-stage, efficient and accurate breeding of the stress-resistant alfalfa material is realized, and the technical problems of long period, low efficiency and insufficient utilization of metabolic information in traditional breeding are solved.

The invention discloses a multi-dimensional efficacy evaluation system for colon cancer targeted drug screening, and relates to the technical field of medical assistance. Comprising a data acquisition module, an inference engine module and an output module. The data acquisition module acquires an organ sample response data set (including apoptosis rate A1, activity decline degree A2 and image structure change score B1) and a patient background data set (including gene mutation discrete variable set G and metabolic pathway continuous variable set M). The inference engine module executes dominant condition rules: generating a negative weight factor alpha according to a gene mutation state and a metabolic activation threshold value; generating a deduction item gamma based on a preset drug-resistant mutation subset; performing weighted calculation on the apoptosis rate and the activity decline degree to generate a basic drug effect score beta, and increasing beta through a critical value; and finally generating a comprehensive response score S. And the output module outputs a drug effect judgment result according to the S, and multi-dimensional accurate evaluation is realized.

The invention discloses a risk assessment method, system and equipment for idiopathic pulmonary arterial hypertension, and belongs to the field of pulmonary arterial hypertension. According to the method, SNP data containing genotypes and effect values, protein marker expression quantity, metabonomics and clinical data are obtained, the SNP effect values are corrected based on linkage imbalance reference information, and PRS is calculated in combination with the genotypes; constructing a protein expression score by utilizing the site effect value and the expression quantity of the pQTL, and fusing the protein expression score with the PRS to form a target PRS; carrying out dimensionality reduction on metabolome data by adopting sparse coding, extracting sparse coefficients of IPAH related metabolic pathways, and converting the sparse coefficients into metabolic pathway scores; converting the clinical indexes into clinical risk scores; based on the clinical parameter distribution target PRS, the metabolic pathway score and the weight coefficient of the clinical risk score, calculating a risk assessment value; and finally, matching the evaluation value with a preset risk threshold value, and outputting a risk evaluation level. And the IPAH risk assessment accuracy of common people is improved.

The invention belongs to the technical field of gene engineering, and discloses recombinant yarrowia lipolytica as well as a construction method and application thereof. The recombinant yarrowia lipolytica PGA1 is obtained by carrying out heterologous expression on an arabidopsis thaliana inositol oxygenase gene and a pseudomonas syringae uronic acid dehydrogenase gene in the yarrowia lipolytica by utilizing a genetic engineering technical means. The recombinant yarrowia lipolytica PGA10 capable of efficiently synthesizing glucaric acid (GA) is finally obtained by further modifying six genes of related metabolic pathways of the recombinant yarrowia lipolytica PGA1. The GA yield of the PGA10 reaches 2233.24 mg / L and is 66.27 times that of PGA1, and the effect is remarkable. The invention not only constructs a GA synthesis method, but also defines the influence of related genes such as opi1 on GA synthesis, and provides reference for the research of heterologous synthesis of GA by microorganisms.

The invention discloses a double-carbon-source mixed fermentation metabolism regulation system for single-cell protein production, and belongs to the technical field of fermentation engineering. The method solves the problems that in the prior art, the independent utilization efficiency of methanol and methane is low, the metabolic pathways of microorganisms to the two carbon sources are different, and high-efficiency single-cell protein production is difficult to realize, and by comprehensively analyzing various data related to historical parameters in the historical parameters, the production efficiency of the single-cell protein is improved. According to the method, key metabolic nodes having significant influence on the yield and quality of the single-cell protein can be accurately identified, and reasonable weights are distributed for the key metabolic nodes, so that the production quality of the single-cell protein in fermentation engineering is optimized, and the realization of a production target is ensured; meanwhile, according to the production target of the actual fermentation engineering, the optimization cost of the key metabolism nodes is evaluated, excessive optimization of high-cost nodes is avoided, the economic benefit of single-cell protein production is improved, the cost budget of the fermentation engineering is reduced, and the flexibility of the fermentation engineering and the scientificity of metabolism regulation decision are enhanced.

The invention provides a teenager disease risk dynamic prediction method and system, and the method comprises the steps: obtaining an electronic health record and subcutaneous metabolite dynamic concentration data of a teenager, and the electronic health record comprises chronic disease related information, a genetic risk value and historical diagnosis data; performing multi-modal fusion on the metabolite concentration data, the genetic risk value and the historical diagnosis data according to a time axis to form a mixed time sequence information set; adaptive optimization is carried out on the mixed time sequence information set, and the collaborative change trend of metabolite fluctuation characteristics and genetic characteristics is identified from the optimized mixed time sequence information set; generating a dynamic graph by adopting a graph neural network based on the collaborative change trend; and tracking an abnormal conduction chain of a metabolic pathway in the dynamic map in real time, and calculating a risk probability matched with the growth stage of the teenagers according to the abnormal conduction chain and chronic disease related information. The dynamic prediction precision and timeliness of the chronic disease risk of teenagers are improved.

The application provides a recombinant Pichia pastoris strain and a construction method and application thereof. The construction method comprises the following steps: taking a Pichia pastoris strain as a host strain, constructing a double synthesis pathway of phenylalanine ammonia lyase and tyrosine ammonia lyase in the host strain to obtain a first engineering strain; relieving the branch acid feedback inhibition of the first engineering strain based on metabolic engineering to obtain a second engineering strain; optimizing the aromatic amino acid synthesis pathway of the second engineering strain to obtain a third engineering strain; knocking out the branch metabolic pathway of the third engineering strain to obtain a fourth engineering strain; increasing the precursor supply of the fourth engineering strain to obtain the recombinant Pichia pastoris strain. The construction method can systematically optimize the synthesis path of p-coumaric acid, and the recombinant Pichia pastoris strain for efficiently producing p-coumaric acid with methanol as a carbon source is constructed. Compared with the host strain, the yield of p-coumaric acid of the recombinant Pichia pastoris strain is significantly improved.

The invention relates to the technical field of sewage treatment, in particular to application of a signal molecule C8-HSL in strengthening sewage treatment of algal-bacterial symbiotic granular sludge. In-depth study finds that the signal molecule C8-HSL can improve the TN removal rate of the system; according to the present invention, with the application of the signal molecules, the flora composition is changed, the enrichment of denitrification functional bacteria such as Hydrogenphaga, Pseudoxanthobacteria and the like is promoted, and the abundance of the complex organic matter degrading bacteria Desulfomicrobe is enhanced; meanwhile, due to the increase of denitrifying bacteria such as Hydrogenphaga, Thauera and Zoogloea, the variety of species is optimized, and the nitrogen removal efficiency and the organic matter degradation efficiency are improved; based on PICRUSt2 analysis, the signal molecule C8-HSL can increase the abundance of the napAB gene and promote aerobic denitrification; expression of nirK and nirS genes is enhanced, and nitrite is promoted to be converted into nitrogen; meanwhile, the signal molecule C8-HSL effectively improves the denitrification performance of the system by optimizing a nitrogen metabolism pathway.

The invention discloses a stem cell metabolism marker omics analysis method, device, equipment and medium, relates to the technical field of biomedicine, is applied to a computer device, and comprises the following steps: carrying out non-targeted detection on a to-be-detected sample of a target object to obtain an original mass spectrum; wherein the sample to be detected is a serum sample or a cell sample; preprocessing the original mass spectrogram to obtain a metabolite matrix in a standardized format; performing principal component analysis and partial least square discriminant analysis on the metabolite matrix, and determining a metabolic marker from the metabolite matrix according to an obtained analysis result; obtaining fragment information of the metabolic marker based on a collision-induced dissociation mode, and searching for a structural annotation of the metabolic marker from a human metabolome database based on the fragment information; and constructing a metabolic pathway map of the metabolic marker according to the structural annotation of the metabolic marker. The accuracy of omics analysis of the stem cell metabolism marker is improved.

The invention relates to a strong promoter P7 suitable for streptomyces and application thereof, and relates to the field of genetic engineering and microbial metabolism engineering. The nucleotide sequence of the strong promoter P7 is as shown in SEQ ID No.1, and the strong promoter comprises a plasmid vector of the strong promoter; a host cell comprising the plasmid vector; the invention also discloses application of the strong promoter, the plasmid vector and the host cell in starting expression of a target gene. Compared with the prior art, the characterization of the strong promoter P7 provides an effective tool element for streptomyces strong promoter engineering and high-efficiency gene expression, and has important significance on streptomyces silent gene characterization, high-efficiency gene expression, metabolite synthesis, metabolic pathway reconstruction and the like. The strong promoter can be applied to common streptomyces type strains, and has important significance on high yield of important proteins including enzymes and important metabolites from actinomycetes.

The invention belongs to the technical field of biochemical engineering, and discloses a production method for improving the content of odd-chain fatty acid in grease by modifying schizochytrium limacinum and optimizing a substrate and application of the method. According to the method, schizochytrium limacinum HX-308 serves as a receptor strain, high-yield odd-chain fatty acid engineering bacteria are obtained through gene overexpression and inhibition, and the high-yield odd-chain fatty acid is obtained. Accumulation of a propionyl CoA precursor pool for synthesizing odd-chain fatty acid is improved, endogenous methylmalonyl-CoA mutase coding gene MUT is inhibited, so that a competitive pathway of the odd-chain fatty acid is inhibited, and then through substrate optimization, the content of fermented grease and the content of the odd-chain fatty acid are obviously improved. The expression of related enzymes in schizochytrium limacinum is adjusted through a genetic engineering strategy to improve the odd-chain fatty acid synthesis, the synthesis and utilization of the key intermediate propionyl coenzyme A in the odd-chain fatty acid synthesis process are increased, the metabolic pathway of the propionyl coenzyme A is inhibited, and substrate optimization is assisted to improve the odd-chain fatty acid yield.

The invention belongs to the technical field of genetic engineering, and particularly relates to a genetically engineered bacterium for producing N-acetylneuraminic acid as well as construction and application of the genetically engineered bacterium. Accumulation of acetic acid is controlled by combining and applying different strategies: rational transformation is performed on an escherichia coli metabolic pathway, and acetic acid synthesis pathway related genes poxB, ackA and pta are knocked out to reduce acetic acid synthesis; the glyoxylic acid cycle is activated by knocking out the coding gene iclR of the glyoxylic acid cycle transcriptional regulation factor, and acetic acid overflow is reduced; the fermentation temperature is adjusted to control overall metabolism of cells to reduce acetic acid accumulation. Through comprehensive application of the strategy, the Neu5Ac production method capable of effectively controlling acetic acid accumulation is obtained, and the method has a good industrial application prospect.

The invention belongs to the technical field of biology, and particularly relates to bacillus velezensis HALZ676 as well as application and a method of the bacillus velezensis HALZ676 to cowhide fermentative degradation, the bacillus velezensis HALZ676 is separated from preserved pig trotters, and by analyzing biological characteristics, whole genome and metabonomics differences of the bacillus velezensis HALZ676, the cowhide can be efficiently degraded, and the cowhide can be efficiently degraded. It is found that peptide components smaller than 3000 Da in cow leather degradation liquid obtained through fermentation of the strain HALZ676 account for 68% or above, and the cowhide degradation liquid has remarkable antioxidant capacity and antibacterial capacity; the cowhide fermentation liquor is mainly used for promoting conversion and enrichment of antioxidant, anti-inflammatory and anti-cancer metabolites through a linoleic acid metabolic pathway, so that the antioxidant, anti-inflammatory and anti-cancer capacities of the cowhide fermentation liquor are enhanced; the cowhide fermented by the strain HALZ676 can enrich functional active components, and a theoretical basis and a promising strategy are provided for high-valued production of processing byproducts of livestock and poultry skin fermented by probiotic bacillus with high yield of collagenase.

The invention provides a method for inhibiting soil acidification and application of protozoa to preparation of biological fertilizer.The method comprises the step that the biological fertilizer containing the protozoa is inoculated into soil, and the protozoa comprises at least one of kidney-shaped worms and ochramydae. By the adoption of the technical scheme, the purpose of rapidly inhibiting soil acidification is achieved, the increase of the organic carbon content of soil can be remarkably promoted, meanwhile, different types of protozoa have different degrees of effects on key nutrient elements such as solid storage nitrogen and phosphorus, and a soil nutrient supply structure is optimized. In the aspect of improving the physical structure of the soil, the life activity of the protozoa can effectively promote the generation of soil aggregates, and the healthy soil structure is remodeled by improving the porosity and air permeability of the soil. In addition, the protozoa can also form a complex interaction network with microorganisms such as bacteria and fungi in soil, so that a microbial metabolic pathway is activated, and the microbial activity is remarkably improved.

The present disclosure provides a recombinant Escherichia coli strain modified by metabolic engineering means and a method for producing L-homoserine by using the same. The strain, designated as Escherichia coli having a strain number of 13-XA, is deposited in China General Microbiological Culture Collection Center (CGMCC) with an accession number of CGMCC No. 25099, dated Jun. 16, 2022. With respect to the chromosome DNA thereof, one or more genes associated with fatty acid metabolism are knocked out or attenuated, and / or a promoter is replaced for enhancement; one or more genes associated with the L-homoserine metabolic pathway are knocked out or attenuated, and / or one or more genes associated with the L-homoserine metabolic pathway are overexpressed or enhanced, and / or one or more genes associated with the L-homoserine metabolic pathway are mutated.

The invention discloses a fermentation process for shortening a fermentation period and efficiently synthesizing Ectoine. The fermentation process comprises the following steps: screening and activating high-yield strains, preparing a fermentation culture medium, performing fermentation culture, performing sectional dissolved oxygen regulation and control, performing double-stage pH dynamic regulation and control, performing carbon-nitrogen ratio dynamic regulation based on metabolic flow analysis, performing osmotic pressure gradient induction in the later stage of fermentation, and extracting and purifying a product. According to the fermentation process for shortening the fermentation period and efficiently synthesizing the Ectoin, the expression quantity of key enzymes for synthesizing the Ectoin is increased by 80% or above compared with that of an original strain through the Halomonassp.ECT-09 strain bred through ultraviolet-nitrosoguanidine compound mutation, the basic yield reaches 35 g / L, a foundation is laid for high yield, and the method is suitable for industrial production. A glucose-trehalose mixed carbon source and a yeast extract-ammonium nitrate mixed nitrogen source are adopted, and an L-aspartic acid-L-asparagine mixed precursor is added, so that the metabolic pathway is shortened, and the loss of an intermediate product is reduced.

The invention discloses a Zymomonas mobilis recombinant strain for producing D-pantothenic acid as well as a preparation method and application of the Zymomonas mobilis recombinant strain. A hydroxymethyl transferase gene panB, a ketopantoic acid reductase gene panE and a pantothenic acid synthase gene panC are integrated in a genome of the recombinant strain; an expression plasmid containing an acetolactate synthase gene Bsals, a keto acid reductoisomerase gene ilvC and a dihydroxy acid dehydratase gene ilvD is also transferred into the recombinant strain; wherein the nucleotide sequences of the gene Bsals, the gene ilvC, the gene ilvD, the gene panB, the gene panE and the gene panC are shown as SEQ ID NO. 1 to SEQ ID NO. 6 in sequence. The zymomonas mobilis ZM4 is systematically modified through a genetic engineering means, and an optimal enzyme combination adaptive to the zymomonas mobilis is defined by screening hydroxymethyltransferase, pantothenic acid synthase and ketopantoic acid reductase from different sources, so that a core foundation is laid for efficient operation of a D-pantothenic acid synthesis route, and the method has a wide application prospect. The technical bottlenecks of single metabolic pathway and low synthesis efficiency of the traditional strain are broken through.

The invention discloses a salicylic acid decarboxylase mutant and application of the salicylic acid decarboxylase mutant in degradation of salicylic acid. The mutant is obtained by carrying out site-specific modification on salicylic acid decarboxylase NahG, and specifically, valine at the 46th site, tyrosine at the 380th site and leucine at the 382nd site of an amino acid sequence shown in SEQ ID NO.2 are mutated into cysteine, phenylalanine and phenylalanine at the same time. The mutant shows remarkably improved catalytic efficiency, and salicylic acid can be efficiently and thoroughly decarboxylated and converted into catechol under mild conditions. The invention also provides a coding gene, a recombinant vector and an engineering bacterium of the mutant. The mutant not only can be used for efficient bioremediation of salicylic acid pollution, but also can effectively break through and accelerate a naphthalene catabolism pathway due to the characteristic of directionally generating catechol, and has important application value in the fields of environmental pollution abatement and biological catalysis.