Effects Of Gut Microbiome Of Black Soldier Fly Larvae (Hermetia Illucens) On The Biod-Egradation Of Food Waste

A large amount of food waste(FW)is produced every year in the world,which greatly threatens the ecological environment and human health.Vermicomposting using black soldier fly larvae(Hermetia illucens)(BSF)have been gradually highlighted as a promising biotechnology for FW management,because it can overcome the defects of FW mainstream disposal technologies,and effectively transform the organic waste into stable biofertilizer and high value-added biomass.Few study has been investigated the contribution of gut microbiome on waste biodegradation,which has been proved that it plays critical role in the host health,environment and metabolism of organic matters.In this study,BSF vermicompost(BV),natural composting(i.e.control group,NC)and BSF gut were selected as the object of study to explore the influence mechanism of BSF gut microbiome on vermicompost bacteria and metabolic function,using high-throughput sequencing technology,PICRUST,co-occurrence network and intrusion theory.The conclusions obtained in this study are as follows:(1)Compared to NC,BV has stronger biodegradability to metabolism organic matter.After BC,the content of C,N,H,S and P were significantly decreased,the reduction rates were 48.8%,61.9%,52.0%,74.1%and 43.5%respectively,which significantly(p<0.05)higher than NC.Dry matter reduction of BV was 38.8%,significantly higher than NC.In addition,beta glucosidase,acid phosphatase and urease activity dropped to 295.8μmol/(g·d)、12105μg/(g·d)、17322 nmol/(g·d),respectively,which were also significantly higher than NC after BV.(2)After inoculating BSF larvae,the a-diversity of vermicompost decreased significantly;microbial community structure was changed greatly;BV’s and BG’s biomarker were Corynebacterium and Dysgonomonas.After BV,part of gut bacteria(12.9%)colonized in vermicompost,and 66.0%of gut bacteria were colonized in vermicompost at the peak.Most of gut bacteria(85.6%)were replaced by the initial bacteria of FW.In addition,we found that BV has stronger external resistance compared to NC.(3)The relative abundance of 11 of 21 metabolic function groups and most functional genes(42.3%)in BV were significantly higher than NC,such as Homoacetogenesis、Carbohydrate Active enzyme、NCA cycle、Hydrogen metabolism、Embden Meyerhof-Parnos and Sulfur compounds metabolism.Only 2 metabolic function groups in NC were significantly higher than that of BV,including methanogenesis and hydrolysis of polymers.And the change of metabolic function and functional genes was significantly correlated with the succession of microbial community.(4)BG bacteria can invade into BV’s niche to influence BV’s microbial community.BV’s bacteria can also invade into BG to influence BG’s microbial community.The interaction between them can create a new niche,and the degradation of organic matter may occur in this new niche.Interestingly,we found that BG’s and BV’s bacteria invasion are mainly mediated by some low abundance of bacteria,including g_Corynebacterium、v_Dysgonomona、g_Sphingomonas、g_Staphylococcusv_Anaerococcus.In addition,BG ’s bacteria invasion is one of the reason leading to the reduction of microbial diversity in BV.