Screening, Characteristic Study Of Fumonisin Degrading Strain And Its Application Exploration

Fumonisins refer to diester compounds with similar structures composed of various multi-hydrogen alcohol and tricarballylic acid.They are water solubility secondary metabolites produced by Fusarium infecting corn and its products under certain conditions.Fumonisins,with neurotoxicity,organ toxicity,immunotoxicity and carcinogenicity,can cause diseases such as pulmonary edema in pigs and equine leukomalacia,and ultimately threaten human health by taking advantage of food chain.The pollution rate of fumonisins in corn,corn distiller’s grains and finished feed is higher than 70%,posing a great threat to human health.During the process of production,methods such as high-temperature cooking,ray irradiation,and chemical reagent soaking can be used to reduce the fumonisin level in the products.However,these methods are not only costly and inefficient,but also easily to destroy the nutrition in grain.In recent years,the biodegradation of mycotoxins in food and feed has become a research hotspot because this method will not destroy the nutrition of grain,nor will it leave any harmful chemicals.Therefore,it is a safe and efficient detoxification method.This paper focuses on the study of fumonisin-degrading fungus as well as their practical applications and mainly includes the following research contents:Taking fumonisin B1(FB1)as the sole carbon source in the mineral salt medium,and a strain FD that can degrade FB1 was obtained by enrichment culture.Through morphological observation and r RNA-ITS sequence analysis,it was identified as Exophyllum spinifera The optimum growth p H of degrading strain FD ranges from5.0 to 6.0 with the temperature of 25 ℃,and the optimum degradation p H is 5.0 to 6.0.In mineral salt medium,degrading strain FD can degrade 10 m L(100 mg/kg)fumonisins within 48 hours.A total of 11,347 annotated gene sequences were obtained by sequencing,assembling and annotating the whole genome of degrading strain FD.Using the whole FD genome as a template,the degradation gene esp was cloned.Insert the obtained gene fragment into p PICZαB vector,and transfer it into host cell X33 by electrophoretic transfer,the recombinant yeast cells was successfully constructed.The expression of degrading enzymes was induced by methanol and the optimal degradation temperature of degrading enzyme was 20-30℃,and the optimal degradation p H is 5.0-6.0.The degradation effect of recombinant yeast in corn feed was studied and the results showed that the recombinant yeast had a good degradation effect on FB1 in contaminated corn and corn products,with a degradation rate of 78%.Adding recombinant yeast at different stages of alcohol fermentation,while FB1 degradation rate reached 67% when detoxification and fermentation were performed after saccharification.