Development of microbial consortium for degradation of organic kitchen waste

Abstract

Increasing population and urbanization has led to an exponential increase in organic waste. This waste if not treated properly may lead to pollution and health hazards. So, a study was conducted to develop an efficient bacterial consortium for the degradation of organic kitchen waste. Different bacterial strains were obtained from MTCC, initially grown on specific media and were screened for their enzymatic activities. Eight bacterial strains viz. Bacillus subtilus (MTCC 441), B. amyloliquefaciens (MTCC 7913), B. megaterium (MTCC 8510), Lactobacillus delbrueckii (MTCC 2365), L. plantarum (MTCC 1407), L. rhamnosus (MTCC 1423), Pseudomonas aeruginosa (MTCC 4673) and Staphylococcus aureus (MTCC 740) were tested for the production of lipase, amylase, protease and cellulase. All the bacterial strains exhibited enzyme activities except B. megaterium. So, combinations of these strains were used to make consortia on basis of pathogenicity. Two different microbial consortiums were prepared with Consortia 1 comprising B. subtilis, L. plantarum, L. rhamnosus, L. delbrueckii, B. amyloliquefaciens and Consortia 2 comprising P. aeruginosa, S. aureus, L. delbrueckii, L. rhamnosus, B. subtilus. Consortium 1 displayed the highest amylase and protease activity as compared to Consortium 2, and therefore selected for monitoring the composting parameters of the organic kitchen wastes. The microbial consortium showed significant outcome for composting parameters such as moisture content (65 – 58 %), temperature (25 – 29 ºC), pH (5.5 – 5.7), organic carbon (41 – 36 %) and decrease in mass (25 %) from 25 to 35 d of composting organic kitchen waste. The C/N ratio was calculated at 38/1 which falls within the optimum composting period. Developing a microbial consortium significantly reduces the degradation time and thereby the composting process. This microbial consortium is environmentally safe and can therefore, be used to effectively improve the management of organic waste at both the community and industrial level.