Affiliation:
1. State Key Laboratory of Rice Biology, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
2. Zhongyuan Institute, Zhejiang University, Zhengzhou 450000, China
Abstract
Alpha-amylases are crucial hydrolase enzymes which have been widely used in food, feed, fermentation, and pharmaceutical industries. Methods for low-cost production of α-amylases are highly desirable. Soybean seed, functioning as a bioreactor, offers an excellent platform for the mass production of recombinant proteins for its ability to synthesize substantial quantities of proteins. In this study, we generated and characterized transgenic soybeans expressing the α-amylase AmyS from Bacillus stearothermophilus. The α-amylase expression cassettes were constructed for seed specific expression by utilizing the promoters of three different soybean storage peptides and transformed into soybean via Agrobacterium-mediated transformation. The event with the highest amylase activity reached 601 U/mg of seed flour (one unit is defined as the amount of enzyme that generates 1 micromole reducing ends per min from starch at 65 °C in pH 5.5 sodium acetate buffer). The optimum pH, optimum temperature, and the enzymatic kinetics of the soybean expressed enzyme are similar to that of the E. coli expressed enzyme. However, the soybean expressed α-amylase is glycosylated, exhibiting enhanced thermostability and storage stability. Soybean AmyS retains over 80% activity after 100 min at 75 °C, and the transgenic seeds exhibit no significant activity loss after one year of storage at room temperature. The accumulated AmyS in the transgenic seeds represents approximately 15% of the total seed protein, or about 4% of the dry seed weight. The specific activity of the transgenic soybean seed flour is comparable to many commercial α-amylase enzyme products in current markets, suggesting that the soybean flour may be directly used for various applications without the need for extraction and purification.
Reference43 articles.
1. Aspects and recent trends in microbial α-Amylase: A Review;Paul;Appl. Biochem. Biotechnol.,2021
2. Biosynthesis and industrial applications of α-amylase: A review;Farooq;Arch. Microbiol.,2021
3. From green plants to industrial enzymes;Hood;Enzym. Microb. Technol.,2002
4. Ashok, P.P., Dasgupta, D., Ray, A., and Suman, S.K. (2024). Challenges and prospects of microbial α-amylases for industrial application: A review. World J. Microbiol. Biotechnol., 40.
5. Protein engineering of bacterial α-amylases;Nielsen;Biochim. Et Biophys. Acta-Protein Struct. Mol. Enzymol.,2000