Screening of bacteria for thermophilic aerobic biodegradation of food waste and the degradation characteristics

Abstract:

[Background] Food waste tends to increase and thus it is an urgent task to rapidly digest it. The thermophilic aerobic biodegradation technology turns to be an effective solution. [Objective] To screen the thermophilic aerobic bacteria which can adapt to food waste and decompose the organic matter in the waste and thereby to improve the degradation efficiency and reduce the waste. [Methods] Experiments on the temperature tolerance in casamino acids, yeast extract, salts (CYS) medium and high-oil and high-salt tolerance in food waste leachate medium were conducted for the primary screening of strains. The enzyme production test was used for re-screening of strains, and food waste biodegradation test for functional verification. [Results] Strains N3-1, C7, N3-3 and G6-1 were finally screened out. The degradation rate of volatile solid (VS) was 36.95%, 33.23%, 32.83% and 31.91%, respectively, 3.02, 2.71, 2.68 and 2.61 times that of the control group. They were identified as Geobacillus thermoleovorans, Bacillus smithii, G. caldoxylosilyticus and G. lituanicus, separately. [Conclusion] The 4 strains have strong adaptability to food waste and high efficiency of degrading the waste. This study lays a foundation for the development of thermophilic aerobic microbial agent and provides technical support for the reduction, harmlessness treatment and resource utilization of food waste.

Key words:food waste;biodegradation;thermophilic aerobic bacteria;Geobacillus;Bacillus