I ISOLATION, CHARACTERIZATION, AND IDENTIFICATION OF MICROORGANISMS FROM RICE MILL WASTE

ABSTRACT Isolation, Characterization, and Identification of Microorganisms from Rice Mill Waste. This study aimed to analyze the microbial contents in rice mill waste, focusing on total heterophilic bacteria count (THBC) and total fungal count (TFC), and to identify the prevalent bacterial and fungal species. Rice mill waste samples were aseptically gathered from five distinct locations around the rice mills in Lafia. The samples were transferred using a spatula into 50g plastic containers that had been sterilized with 70% alcohol beforehand. A 10-gram portion of each sample was then homogenized in sterile distilled water, followed by a series of dilutions (5-fold). The diluted samples were inoculated onto nutrient agar and potato dextrose agar plates using the pour plate technique. Following inoculation, the plates were incubated at 37°C for bacterial growth and 25±2°C for fungal growth, with subsequent subculturing carried out to obtain pure isolates on selective media. The results revealed that THBC ranged from 4.8 x 104 to 9.2 x 104 CFU/g, while TFC ranged from 2.2 x 104 to 6.9 x 104 CFU/g. Identified bacterial isolates included Bacillus spp., Pseudomonas spp., and Lactobacillus spp. Fungal isolates included Aspergillus spp., Penicillium spp., and Saccharomyces spp. The study reveals significant microbial diversity in rice mill waste, with varying counts of bacteria and fungi. The findings contribute to understanding the microbial load in agricultural by-products and its implications for waste management. Keywords: Rice mill waste, Total heterophilic bacteria count, Total fungal count, Microbial diversity, Waste management