7 results about "Cysteine synthesis" patented technology

The present invention relates to the field of biotechnology, and more particularly to a highly active S-sulfo-L-cysteine ​​synthetase mutant and its applications. The present invention screened and identified a preferred SSC03 enzyme through cluster analysis and phylogenetic analysis, and further engineered mutations thereof. The resulting SSC03-S256PΔCT achieved a 24-hour conversion rate of 56% and produced 84 mM of S-sulfo-L-cysteine, demonstrating its applicability to further purification process development.

The application discloses a mutant of glutamate-cysteine synthetase and application of the mutant in synthesis of glutathione. Single-site mutation is carried out on amino acid residues at positions 150, 188, 235, 236, 241, 300, 301, 302 and 330 of wild-type glutamate-cysteine synthetase (Glutamate-cysteine ligase [EC:6.3.2.2]) from Citrobacter koseri (strain ATCC BAA-895), and mutant sites at positions 150, 236, 302 and 330 are screened. Mutants M1-M6 are obtained by combination mutation of the mutant sites screened above, and the enzyme activity of the mutant M4 with the highest activity is increased by 477% compared with that of the wild-type glutamate-cysteine synthetase. The mutant M4 is used to catalyze synthesis of glutathione, and the highest concentration reaches 23 g / L, which is increased by 4.2 times compared with the wild type, and the production cost is greatly reduced, so the mutant has important application value.

This invention belongs to the field of microbial technology and provides a space-mutated *Bacillus paralichrysiformis* strain with high synthetic selenocysteine ​​and high sodium selenite tolerance, obtained through space mutagenesis, and its applications. The *Bacillus paralichrysiformis* G1-m strain is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 36525, deposited on November 11, 2025. This strain has significant core advantages: firstly, it possesses extremely high sodium selenite tolerance, able to withstand sodium selenite stress up to 440 mM; secondly, its selenocysteine ​​and nano-selenium synthesis efficiency is significantly improved, not only significantly increasing the strain's resistance threshold to selenium stress but also directionally enhancing the activity of the selenocysteine ​​biosynthetic pathway. Its application potential covers multiple fields, such as selenium-enriched probiotic preparations, nano-drug carriers, functional food additives, and high-efficiency selenium nutritional supplements, laying the foundation for the high-value utilization of selenium resources and the industrial application of functional microorganisms.

The invention discloses a bacillus licheniformis recombinant strain with high yield of L-cysteine, and belongs to the technical field of synthetic biology and microbial metabolism engineering. The cysteine synthesis flux is enhanced through multiple knockout and combined overexpression. An efficient engineering strain is constructed by knocking out a serine hydroxymethyltransferase coding gene glyA and an L-serine ammonolysis enzyme coding gene sdaAA of a serine catabolism key pathway, knocking out a cysteine catabolism gene metC and combining gene overexpression to introduce a feedback inhibition removal mutant cysEf and a transporter eamA, and the efficient engineering strain is used for preparing a recombinant strain. Finally, the yield of the L-cysteine reaches 1.075 g / L in shake flask fermentation (the conversion rate is 18.69%), and the application potential of the bacillus licheniformis in sulfur metabolism engineering is highlighted.

The application discloses a novel low-temperature curing epoxy curing agent and a preparation method thereof, and belongs to the technical field of epoxy curing agents. The novel low-temperature curing epoxy curing agent is made of eugenol, cysteine and formaldehyde. The application selects raw materials through a large number of experiments, adopts new raw materials, i.e. eugenol and cysteine. The eugenol molecule contains a phenolic hydroxyl group, an allyl group and a methoxyl group; the cysteine molecule contains an amino group, a carboxyl group and a sulfydryl group (-SH). These groups increase the reactivity of the curing agent, and especially the sulfydryl group can greatly improve the curing speed of the curing agent in a low-temperature environment. The phenolic aldehyde amine curing agent synthesized by using eugenol and cysteine has a faster low-temperature curing speed than a general cardanol phenolic aldehyde amine curing agent, and also has a good heat deformation resistance, and thus a good technical effect is achieved.

Processes for producing L-cysteic acid along with uses for the same. The process includes providing a reaction of O-phospho-L-serine (OPS) with a salt of sulfurous acid (sulfite) and a cysteate synthase (CS enzyme) belonging to enzyme class EC 2.5.1.76 in a biotransformation. Where a concentration of OPS in a batch is at least 1 g / L and the CS enzyme is produced in an enzymatically active form by growth of the microorganism strain E. coli K12 JM105. The biotransformation is carried out under active pH control and the CS enzyme has an amino acid sequence specified in SEQ ID NO: 4 or an amino acid sequence homologous thereto. Where an amino acid sequence homologous to SEQ ID NO: 4 has a sequence identity of at least 50% in relation to SEQ ID NO: 4 and, at the same time, cysteate synthase enzyme activity.

The invention provides an Escherichia coli mutant strain with high yield of L-cysteine and application, and belongs to the technical field of bioengineering, the strain is named as MFAPA45QT, and the preservation number of the strain is CGMCC (China General Microbiological Culture Collection Center) NO: 31970. According to the method, molecular modification means such as metabolic engineering and the like are combined with a traditional breeding method, and through mutation sites existing in 3-phosphoglycerate dehydrogenase and serine acetyltransferase, feedback regulation on key enzymes in the L-cysteine synthesis process is effectively relieved, and the yield of L-cysteine is increased; the escherichia coli mutant strain MFAPA45QT is obtained by carrying out ARTP mutagenesis coupling L-cysteine specific response biosensor high-throughput screening, the L-cysteine yield in a fermentation tank level can reach 31.11 g / L, and the method is suitable for industrial production of L-cysteine.