Mechanism And Application Of Patulin Removal By Aspergillus Niger FS10 Based On Multi Omics Technology

Mycotoxin contamination not only causes the serious economic losses of the countries,but also present the health challenge of people and animals,which becomes a key global problem.Patulin(PAT)is mainly produced by Penicillium expansum and exists in fruits,vegetables and their derivatives.PAT is extremely toxic and able to harm the kidneys,liver,immune system,gastrointestinal system.Therefore,it is urgent to establish a safe and effective measure of PAT prevention and control.Biodegradation methods is more environmental,economical and safer when compared to physical and chemical detoxification methods.However,the degradation efficiency was been studied much more than the toxins tolerance and degradation mechanism of strains at present.In this paper,the degradation effect and the detoxification ability of Aspergillus niger FS10 on PAT was studied,and the tolerance of strains and the mechanism of toxin degradation was explored by means of omics,which provides new methods and idea of PAT control and mycotoxin biological control.The results of this paper are as follows:(1)The toxin degradation effect of the component of A.niger FS10 with high degradation efficiency on PAT was studied.The bacterial suspension showed the most efficient degradation efficiency with 94.72%removal rate of PAT after co-culture with suspension for 36 h,and PAT could be removed completely after40 h.The fermentation broth showed the weakest removal effect with 5.36% degradation rate,PAT could be degraded well by mycelium and spores,however,the degradation rate decreased 64.01% after heated treat with mycelium,which indicated that PAT could be degraded by a certain intracellular active substance of A.niger FS10.When induced by PAT,the active substance could be produced more.The identification of degradation production showed that PAT could be converted into ascladiol by A.niger FS10.The toxicity of the degradation products was evaluated by the cell evaluation model of human liver cancer cells(HepG2)in vitro,which showed that the treatment of A.niger FS10 could eliminate the toxicity of PAT on cells.(2)The effect of metabolic response of PAT on A.niger FS10 during the degradation process was researched.Principal component analysis(PCA)showed that metabolism of A.niger FS10 was great influenced by PAT stress when treated after 24 h in the three time groups of 24 h,36 h and 48 h.The clear clustering could be observed not only after treated by PAT,but also the control with the prolonged the treatment time,and the clustering degree in the high concentration group was higher when compared to low concentration group,which indicated that high PAT concentration is beneficial to improve the tolerance of A.niger FS10,thereby activating the biological self-repair ability.The results of KEGG indicated that glutathione metabolism pathway was involved in the whole process of PAT stress on A.niger FS10,and the content of glutathione was found to be change dynamically with the PAT degradation after monitored during the process.(3)The differential proteins and genes during the degradation of A.niger FS10 was analyzed by the proteomics and transcriptomics.The results showed that vitamin B6 metabolic pathway has been significantly enriched,which is line with the results in proteomics and transcriptomics.It is deduced that the degradation of PAT is related to metabolism of vitamin B6.Glutathione S-transferase and pyridoxine 4-dehydrogenase were significantly up-regulated which was regulated by Q0CCY0.1 and O14295.1respectively after the treatment with PAT according to the combined analysis of proteome and transcriptome,and the significantly changed proteins were mapped to glutathione and vitamin B6 metabolism pathway.Synthesis and further overexpression validation of Q0CCY0.1 and O14295.1 showed that the PAT degradation of overexpressed strain was significantly improved,suggesting that the PAT degradation by A.niger FS10 is closely related to glutathione S-transferase and pyridoxine 4-dehydrogenase.(4)A.niger FS10 was used to degrade PAT in apple pomace feed,and the degradation conditions were optimized.The optimal treatment conditions in fermentative degradation were: inoculation volume 10%,31?for fermentation temperature,4 d for fermentation time,and 1:3.2 for the ratio of material to water.Here,patulin in apple pomace can be completely removed.Evaluation of nutrients in apple pomace before and after fermentation found that the crude fiber content in apple pomace was decreased 2.94%,the crude protein content was increased 1.92%,the crude fat content was increased 0.74%,total amino acid content was increased 9.35 mg/g.