Biosurfactants And Their Application On Composting Of Municipal Solid Waste

With the development of economy and the increasing production of municipal solid waste, how to improve the quality of compost and reduce the cycle of composting has become of more and more interests. Biosurfactant, a new surfactant which is environmental acceptable, is expected to have the potential to ameliorate the microenvironment in composting and increase the quality of compost when it is added.In the study, rhamnolipid biosurfactant was produced and the optimal condition for Pseudomonas aeruginosa from China Center for Type Culture Collection to produce the biosurfactant was determined. The biosurfactant was also separated and purified from its broth. Furthermore, it was identified and the results verified the existence of the surfactant, which was preparation for the next experiment.For better application of the biosurfactant into municipal solid waste degradation process, in the study biosurfactant-producing bacteria were screened from compost. The results showed Bacillus subtilis were the main biosurfactant-producing bacteria in composting.Next, the culture liquid of rhamnolipid produced by Pseudomonas aeruginos was applied to the vegetable substrate degradation process to examine the stimulative role of rhamnolipid broth on the process and to simply disclose the mechanism. The experiment result showed that rhamnolipid broth can enhance the degradation process of vegetable substrate. Consequently it may accelerate the degradation process of readily degradable organic matter in composting.Because of more and more serious pollution of oil hydrocarbon in soil and the limited application of synthetic surfactants to remove such contaminants, in the study two biosurfactants were used to help degrade the oil hydrocarbon in soil, using composting method. The results showed that biosurfactant surfactin and rhamnolipid can facilitate degradation of the oil hydrocarbon in composting with different degree and rhamnolipid functioned more positively than surfactin.Some physiochemical and biological characteristics of biosurfactant and its application into composting were investigated in the paper. Its positive function on vegetable substrate degradation and oil hydrocarbon removal from composting soilwas also validated. The subject suggested a new study field and the work may be helpful to the coming researchers.