Study On Environmental And Microbial Conditions Of Food Waste Transformed By Black Soldier Fly

Black soldier fly is a kind of insect treatment method of organic solid waste developed in recent years.Because the treatment products are insect feed protein and insect sand organic fertilizer,the treatment products have good economic value and the treatment process conforms to the concept of green and sustainable development,so it has been rapidly developed and applied.However,there are still many deficiencies in the technology of kitchen waste treatment by black soldier fly,which need to be studied and explained urgently,mainly as follows:1)The effects of nitrogen source conditions and C/N ratio(C/N)range of food waste substrate on the treatment efficiency of black tabby are not clear enough.The effects of inorganic and organic nitrogen sources on the treatment process of black tabby,as well as the optimized C/N conditions need to be studied and explained urgently in order to strengthen the efficiency of insect recycling of food waste.2)There is a large amount of oil in kitchen waste,and the oil treatment is incomplete.Therefore,it is necessary to find ways to enhance the removal of oil.The use of calcium-containing minerals and microorganisms may enhance the hydrolysis,neutralization,enzymatic hydrolysis and bioutilization of oil.In view of the above shortcomings,this topic plans to add nitrogen source substrate,regulating C/N,adding calcium minerals,as well as inoculated microorganisms as the main technical means,black soldier under different conditions by comparing the fly's growth and development level,the reduction rate of the garbage,black soldier fly's production rate,conversion rate,conversion efficiency and grease composition,found that optimization of the environment and the microbial conditions,The results show that C/N,calcium minerals and microorganisms affect the recycling process of food waste black soldier fly.Nine nitrogen source substrates,NH4Cl,NaNO₃,urea,uric acid,L-Gly,L-Glu,L-Glu:L-Asp(1:1,w/w),soybean meal and fish meal,were added into kitchen waste.It was found that adding 1 g/100 g(dry wt)N to kitchen waste,The two inorganic nitrogen sources,NH4Cl and NaNO₃,caused significant harm to the survival of larvae and the waste conversion process,while the seven organic nitrogen sources had no effect on the waste disposal process of larvae,indicating that organic nitrogen is a more safe nitrogen source regulator.Urea had no effect on the amino acid composition of the larvae,but had some effect on the enzyme activity.By adding 0%-10%Ca CO₃,0%-10%Ca(OH)₂,a mixture of 5%Ca CO₃and bacterial solution,and 6 different bacterial solutions to kitchen waste,the effects of calcium minerals and microorganisms on lipid reduction and conversion efficiency of insect oil were studied.The results showed that adding calcium minerals to the kitchen waste could significantly regulate and buffer the environmental p H value during the treatment process of black gadfly,but had no significant effect on increasing the oil removal efficiency and oil conversion capacity of black gadfly.Adding only microbial liquid is the most effective method to improve waste oil reduction rate and black soldier fly oil enrichment rate.Bacillus subtilis NJZ strain,Bacillus licheniformis NY strain,Lactobacillus plantarum RS72 strain and Enterococcus faecalis L102 strain are the effective strains to improve the oil conversion efficiency of black gadfly.However,even after microbial inoculation,29%to 44% of the oil in the insect sand was still left at the end of treatment,indicating that the oil in kitchen waste was difficult to be completely degraded and utilized.In the future research,we can continue to screen the highly efficient oil-degrading microorganisms and treat the kitchen waste together with black soldier flies,aiming to realize the full utilization of oil components.