Sustainable Solid Waste Management: Isolation of Cellulolytic Microorganisms from Dumpsites in Lagos, Southwest Nigeria

Abstract

Municipal solid wastes is composed of 4050% cellulose, 9-12% hemicelluloses 1015% lignin on a dry weight basis (Rani and Nand, 2000; Gautam et al., 2010). These waste materials could be turned from liabilities into assets. Microorganisms which This research was to carry out an environmental surveillance for cellulosedegrading microorganisms present in wastes dumpsites in Lagos, southwest Nigeria. Solid waste has become a heavy burden to both government and citizens in developing countries all over the world due to increase in population. The presence of cellulolytic microorganisms and their potential to degrade the complex polymer; cellulose into simple sugars like glucose under optimum environmental conditions were also evaluated. Soil and leachate samples were collected (0 -10cm depth) from three dumpsites in Lagos following aseptic procedures and the microbial species were isolated using Nutrient agar and Potato-dextrose agar media respectively. A total of 34 microorganisms were isolated from the three different sampling locations in Lagos. The cellulase-producing microbial species were characterized following conventional and standard microbiological methods. They were then screened for cellulase activity using the Cellulose Congo-Red plate technique. The diameters of clear zone of inhibition were measured in millimeters (mm). All isolates were cellulase producers, with Bacillus licheniformis having 42.5% occurrence, as well as the highest cellulase activity and hydrolytic value (34mm and 8.5 respectively) among the bacterial species while Aspergillus sp.(40.0% occurrence) had the highest cellulase activity (63mm) and hydrolytic value (15.8) among the fungal species. This result suggested that these microorganisms utilized the available sources of cellulose present in wastes both for growth, biomass production and biodegradative processes. Consequently, the introduction of these microorganisms into waste recycling processes will enhance the sustainable solid waste management practices for megacities as well as the quality of public health in developing economies. K e y w o r d s