Microbial Succession And Lignocellulosic Degradation And Nutritional Quality During Oyster Mushroom Cultivation Of By Short-Term Peach Sawdust-Based Composting

In order to make full use of sawdust resources as the raw material for oyster mushroom cultivation,this study used the Pleurotus ostreatus formula culture material as the test material,and used the fermentation material short-time high temperature process for composting and mushroom cultivation.For mixing period(C0),composting 3 d(C1),composting 6 d(C2),composting 9 d(C3),composting end(C4)and before inoculation(S),mycelial germination(G1),mycelial growth To half(G2),full of mycelia(G3),primordia(G4),first-flush fruiting(G5),and the end of total fruiting(G6),the culture material was sampled,and its temperature and physicochemical properties(p H)were measured.,electrical conductivity,water content,carbon content,ash content,nitrogen content,organic matter,carbon-nitrogen ratio),lignocellulose content,related degrading enzyme activities,and the biological efficiency of fruiting was calculated.High-throughput sequencing and metagenomic sequencing of ITS r RNA and 16 S r RNA genes were used to deeply analyze the dominant species,succession laws and related metabolic pathways of composting microorganisms.Taking the clinker process as a control,the physical and chemical properties of the substrate,the nutritional quality of fruiting bodies after fruiting,amino acids and antioxidant activities of the two different treatments were compared and analyzed.The result is as follows:(1)In the composting process,temperature is the most important factor in the composting process,and the thermophilic stage exceeding 50℃ lasted for 8 days,which promoted the decomposition of the compost.The trends of organic matter,total carbon,and carbon-nitrogen ratio were similar.As the composting progressed,the total nitrogen and ash content increased,and the electrical conductivity also fluctuated.At the end of composting,lignocellulose was degraded by20.5%,47.13%,and 40.75%,respectively.Moisture is the key factor in the early stage of composting,and total nitrogen,temperature and lignin become the main factors affecting the maturity of composting.(2)At the mixing period composting(C0),the relative abundance of Actinobacteria(54.3%)was the highest,followed by Proteobacteria(25.1%)and Firmicutes(8.0%).Proteobacteria(44.2%)reached the highest relative abundance levels during the thermophilic stage and remained in a relatively stable range(9.8～11.6%)during successive thermophilic stages from 6 days of composting(C2)to the end of composting(C4)stage.(3)Composting increased pathway genes related to carbon cycle,such as: carbon metabolism,pyruvate metabolism,prokaryotic carbon fixation pathway,starch and sucrose metabolism pathway,glycolysis/gluconeogenesis pathway,tricarboxylic acid cycle,etc.Thermophilic microorganisms in the composting process promote the metabolism of carbohydrates and amino acids,and also accelerate the abundance of glycolysis and tricarboxylic acid cycle genes,resulting in an increase in the abundance of carbohydrate-active enzymes,thereby driving carbon metabolism and promoting degradation of lignocellulose.(4)Streptomyces and Saccharopolyspora showed a very significant positive correlation.Acinetobacter was significantly negatively correlated with Thermobisporus and Pseudomonas.In the composting process,the top 20 bacterial genera were all correlated,and both positive and negative correlations were found.Synergy and competition promoted the whole composting process.Enzyme genes(GHs and AAs)directly involved in lignocellulose degradation are mainly from Pseudoxanthomonas,Microbispora,and Streptomyces,which are directly involved in the degradation of lignocellulose..(5)The pH value,total carbon content and total nitrogen content of the substrate are the key parameters that significantly affect the quality and biological activity of mushrooms.The degradation rates of lignin during mycelium growth and fruiting of the two cultivation processes were similar,and the degradation rates of cellulose and hemicellulose in the clinker control group were twice that of the short-term high-temperature process.The composting process reduced the total nitrogen content of the substrate,and further reduced the content of crude protein,total amino acids and essential amino acids in mushroom fruiting bodies.(6)The biological efficiencies of oyster mushrooms with two different treatments were 82.5%(experimental group)and 78.8%(control group),both of which accounted for the highest proportion of first-flush mushroom yield in total fruiting.The biological efficiency and crude fiber content of Pleurotus ostreatus cultivated by the short-time high temperature process were significantly higher than those of the control group,but the other main nutritional qualities(crude fat,crude polysaccharide)and the scavenging rates of ABTS·+ and OH·free radicals were significantly lower than those of the control group.Group.