Processing Solid Organic Wastes Employing Maggots Assisted By Microbe And Development Of The Relevant Products

With the economic developing, solid organic wastes such as pig manure and gibberellin industrial fermentation wastes are generated more and more. If not properly processed, it will induce the environment pollution and resources waste. Housefly (Musca domestica Linnaeus), flesh fly (Boettcherisca peregrine) and blow fly (Chrysomya megacephala Fabricius) can digest this organic wastes assisted by microorganisms to inhibit pathogenic microorganisms and eliminate odor. These larvae fed on gibberellin wastes and pig manure is rich in fat and protein, and it has a broad application prospects in the field of bio-energy and animal feed fields.The initial flies were obtained by trapping, and were reared to breed in the laboratory; then we investigated the effects of egg productivity on oviposition substrates and adult density in a large-scale breeding for blow fly; to improved the gibberellin degradation rate, we screened two bacterium from marine strains, which can ferment organic wastes and assisted housefly larvae to process gibberellin wastes; the oil were extract from housefly and flesh fly larvae derived from pig manure and gibberellin wastes were used to produce biodiesel by acid-catalyzed esterification and alkali-catalyzed transesterification reaction and we optimized production parameters; housefly larvae meal was used to replace the fishmeal in the loach (Misgurnus anguillicaudatus) commercial feed. The growth characteristics, loach muscle amino acids and fatty acid composition were evaluated. The main findings are as follows:(1) Collecting cyclorrhapha flies, and blowfly large-scale rearing.Housefly, flesh fly and blowfly were the main species that participated in pig manure decomposition; when 10% blood meal was added in the wheat bran as the oviposition substrate, the egg yield and larvae hatching rate are superior; the optimum adult density was 5075/m3, and the peak spawning period was the third week after adult emergence, lasting 6 weeks.(2) Processing gibberellin wastes employing housefly assisted by microbe.We get two marine bacterial strains with gibberellin degradation capability, and they were identified to Staphylococcus saprophyticus and Corynebacterium variabile; gibberellin wastes was added 40% straw powder,65% water, pH 8.5, then inoculated yeasts and Corynebacterium variabile, cultured for 6 days in 26℃.85.52% gibberellin was eliminated after solid state fermentation; the result of pilot-scale experiment showed that From 100 kg of culture medium (containing 60% gibberellin wastes), we can obtain approximately 12 kg fresh housefly larvae and 48 kg organic fertilizer daily; the gibberellin residual in the fresh larvae was lower than the Japanese fruit minimum standards.(3) Using oil from housefly and flesh fly larvae to produce biodiesel and optimizing the process.The oil content of flesh fly larvae fed on pig manure and gibberellin wastes was ranged 19.5%-21.7%, and the larvae cycle was just 4 days; flesh fly larvae oil optimum esterification conditions:12:1 methanol to oil molar ratio,1.5% catalyst,70℃ for 120 min reaction time; most of the flesh fly biodiesel properties met the USA national biodiesel standards (ASTM D6751), such as, density 884.2 kg/m3, viscosity 5.6 mm2/s, flash point 146℃, cetane number 51.5 and ester content 98.6%; the oil content of housefly larvae fed on pig manure was up to 21.6%, the optimum conditions of the housefly oil esterification:8:1 methanol to oil molar ratio,2% catalyst,70℃ for 120 min reaction time; the housefly biodiesel properties:density 881 kg/m3, viscosity 5.64 mm2/s, flash point 145℃, cetane number 52.3 and an ester content of 96.8%.(4) Performance, amino acids and fatty acids of loach fed housefly larvae meal as a replacement for fish meal.When 75% of fish meal was replaced by housefly larvae meal, feed conversion ratio was significantly lower than the control group (P< 0.05), but no significant difference in weight gain and survival rate (P> 0.05), a significant reduction in the crude ash of loach muscle (P< 0.05) compared with the control group; the total essential amino acid content of 50% and 75% of fish meal replacement group were higher than that of control group, And the coefficient of variation of several amino acids, such as aspartic acid, glycine and glutamate were relatively high. With the control group increasing, a downward trend in the relative content of saturated fatty acids was observed, but the unsaturated fatty acids had an upward trend.