Process Of Lysine Yield Increase In Feed From Potato Pulp And Bioinformatics Analysis Of Related Enzyme

The spoilage of proto-starch processing wastes including potato pulp and wastewater which are full of nutrition and organics caused environmental pollution resulting from the stench, and therefore they cannot be discharged directly. A great deal of potato-starch processing wastes piled around the plant, not only greatly limit the development of enterprises but also waste valuable resources. Currently, the traditional physical and chemical methods cannot solve the problem of pollution effectively. The use of microbial technology makes the waste can be transformed into single cell protein (SCP) effectively which is absorbed and utilized by animals. To improve the quality of this SCP, the first limiting amino acid, lysine, in animal feed and the content of crud protein were increased through optimization of fermentation processing by adding high lysine and nitrogen-fixing bacteria.The mixture of potato pulp and wastewater was transformed into SCP through fermentation in a 5 L airlift bioreactor. The best strain combination was determined through single strain and strain combination experiment which was Bacillus pumilus E1: Candida utilis: Aspergillus niger: Azotobacter chroococcum=7:2:1:5 with inoculums concentration of 0.7 , 0.2 , 0.1 and 0.05 , respectively. A L₁₆(4³) experiment was designed based on the result. After optimizing the process, the best fermentation conditions were: temperature, 40℃; the amount of substrate, 3%; initial pH, nature (about 7.0). Under optimized conditions, SCP was produced through fermentation. Components of SCP including lysine, crud protein, true protein, acid detergent fiber, neutral detergent fiber, crud fat, water and ash were analyzed to evaluate the nutrition level of the SCP feed produced from potato-starch processing wastes comprehensively.Bioinformatics was used to analyze the key enzyme and related genes in lysine biosynthesis in Bacillus pumilus. Promoters and transcription factor binding sites of 5' upstream region in three aspartate kinase genes searched in NCBI were predicted. The protein properties, domains, secondary structures, and 3D structures of the three aspartate kinase were analyzed.