A kind of method utilizing cadmium rice to produce trehalose

Abstract

The synthetic sequence is SEQ NO1 metal-affinity polypeptide BMP and displayed on the surface of Pichia pastoris to construct BMP genetically engineered bacteria for reducing cadmium in cadmium rice. Sugar synthase; cadmium rice is separated by grinding, liquefaction, and pressure filtration to obtain cadmium protein and liquefied syrup; The engineered bacteria were added to the cadmium protein decomposition solution, stirred to absorb cadmium, and centrifuged to obtain cadmium-absorbed yeast and rice protein peptide; the rice protein peptide was used as the main component of the fermentation medium of TerS genetically engineered bacteria, and the fermentation and expansion culture of it was produced. Homogenize the bacterial solution and crush it to obtain the TreS crude enzyme solution, add it to the maltose syrup for catalytic reaction, and then carry out corresponding treatment to make full use of cadmium rice to produce trehalose.

Description

technical field [0001] The invention belongs to the field of food processing and biotechnology, and specifically relates to a method for producing trehalose by using biotechnology to construct genetically engineered bacteria for cadmium-excessive rice (referred to as cadmium rice) for processing and producing trehalose. Background technique [0002] Cadmium rice generally refers to rice with excessive cadmium content (China’s national standard is 0.2 mg / kg). In the past few decades, due to the one-sided pursuit of GDP growth and the lack of attention to environmental protection, China's soil pollution has become more and more serious, and heavy metals such as cadmium in rice have exceeded the standard. The market randomly purchased samples, and the results showed that about 10% of the commercially available rice had cadmium exceeding the standard; in the Guangdong cadmium rice incident in 2013, it was reported that the cadmium rice flowing from Hunan, Jiangxi and other place...

AI Technical Summary

Problems solved by technology

In the past few decades, due to the one-sided pursuit of GDP growth and the lack of attention to environmental protection, China's soil pollution has become more and more serious, and heavy metals such as cadmium in rice have exceeded the standard. The market randomly purchased samples, and the results showed that about 10% of the commercially available rice had cadmium exceeding the standard; in the Guangdong cadmium rice incident in 2013, it was reported that the cadmium rice flowing from Hunan, Jiangxi and other places to Guangdong exceeded the national standard by up to 6 times; For a long time, China will face a large amount of cadmium rice processing problems; the research of Yang Jurong and others shows that cadmium in rice is mainly combined with protein, less with starch; and the current methods of cadmium removal are mostly concentrated on physical or chemical methods. There are few biological methods to remove cadmium, and there is even a lack of research on processing cadmium rice into high value-added products such as trehalose after removing cadmium

[0003] Trehalose (Trehalose) is a non-reducing disaccharide composed of two molecules of glucose connected by α, α-1, 1-glycosidic bonds. It is known as a The large-scale production methods of "sugar of life" and "new sugars in the 21st century" have attracted widespread attention; trehalose is now mainly produced by double-enzyme method or single-enzyme method, and the single-enzyme method uses maltose as raw material. The use of one enzyme has the advantage of simplicity, but the existing trehalose synthase has the disadvantages of low reaction temperature, easy contamination of bacteria, long reaction time, and low conversion rate. Genetically engineered bacteria often use glycerol as the main component of fermentation medium, and the cost is high. These shortcomings have seriously affected the promotion and application of the single-enzyme method.

[0004] Yeast cells displaying proteins or enzymes have the advantages of being immobilized and reusable, and also have the characteristics of simple preparation, high-density culture to obtain a large number of bacteria, and low cost. Therefore, since their appearance at the end of the last century, they have developed rapidly and have many reported that a protein or enzyme was successfully expressed; Feng Xia et al. (Cd based on display technology 2+ Binding peptide screening and yeast heavy metal adsorption research [J]. Henan Agricultural Sciences, 2013, 42 (9): 142-145) reported that dodecapeptide was displayed on Saccharomyces cerevisiae EBY100, and after 24 hours of induction, it was able to adsorb Cd 2+ yeast, but its Cd 2+ The adsorption rate is not high, only 30.4%

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