MOLECULAR AND BIOCHEMICAL CHARACTERIZATION OF AUTOCHTHONOUS CELLULOLYTIC MICROORGANISMS FROM THREE LANDFILL SITES IN LAGOS, SOUTHWEST NIGERIA

Abstract

This study was conducted to evaluate and identify native cellulolytic microorganisms to tropical sanitary landfill sites in Lagos, Southwest Nigeria as well as to provide insights into the potential of autochthonous microorganisms in solid waste management. Soil and leachate samples were obtained simultaneously (0 – 30 cm depth) at the same time from three waste dumpsites in Lagos, using aseptic procedures. Thereafter, composite soil samples and leachates were generated independently and transported to the laboratory for analysis. Microorganisms were isolated from both soil and leachate samples using the serial dilution technique on sterile nutrient agar (NA) and potato dextrose agar (PDA). Subsequently, cellulase-producing microbial species were identified using conventional and standard microbiological techniques as well as by cultivation on Starch-casein-agar. Pure cultures of isolates were inoculated on sterile filter paper placed on Starch - casein agar plate. Isolates were selected based on their metabolic capabilities to utilize the filter paper for growth. Screening for utilization of aromatic acids was carried out in 250 mL conical flasks containing composition: minimal agar medium (pH 7.2), 1.0 g/L aromatic acids (vanillic), 1.0 mL trace elements, phosphate buffer and Bromothymol blue as pH indicator. The DNA of some selected isolates with cellulolytic activity were extracted and sequenced using 16S rRNA sequencing, ITS, and bioinformatics tools. Consequently, among the bacterial species, Bacillus sp. had the highest cellulose degradative ability and was the most prevalent (50%) in occurrence among bacterial species while Aspergillus sp. emerged as the most commonly occurring fungal isolate (35.7%). Data of selected sequenced cellulolytic isolates were deposited at NCBI GeneBank with Accession numbers: KP843680.1 (Vibrio tubiashii), MK748310.1 (Aspergillus aculeatinus), LC496490.1 (Aspergillus aculeatus), CP029751.1 (Staphylococcus aureus) and JX144699.1 (Bacillus mycoides). Environmental surveillance of these microorganisms with microbial synergistic capabilities, could transform solid waste management into a highly efficient biotechnological process that facilitates volume reduction, waste recycling and Bioenergy production.