Screening and Evaluation of Potential Cellulose Degrading Bacteria from Food Wastes of Wolkite University Student’s Cafeteria
Abstract
Debebe Landina Lata
Food waste, which includes unwanted portions of raw or cooked food discarded during or after preparation, is a significant contributor to environmental pollution. This waste is rich in cellulose, an organic compound. This study aimed to screen and evaluate cellulose-degrading bacteria from waste foods. Bacterial isolates were cultured on a carboxymethylcellulose screening agar medium for this purpose. These isolates were further characterized based on their morphological and biochemical properties and were optimized for growth conditions, including pH, temperature, and heavy metal tolerance. From the initial screening, 30 bacterial isolates were obtained, of which 10 demonstrated cellulolytic activity. Among these, 4 isolates exhibited the highest cellulolytic activity, as determined by their cellulolytic index values. All 4 isolates were found to be gram-negative, non-motile, and tested negative for the oxidase, catalase, and Voges-Proskauer (VP) tests. However, they tested positive for the methyl red (MR) test, urease test, and citrate utilization test. Optimal growth was observed at a neutral pH of 7 and a temperature of 35 °C. Additionally, these isolates showed significant tolerance to mercury in the heavy metal tolerance assay, withstanding concentrations between 0.01% and 0.02%. These findings offer a valuable foundation for identifying and evaluating potential cellulolytic bacteria, which could be utilized in bioethanol production and other industrial applications. Further research is needed to carry out the molecular characterization of these cellulose-degrading bacteria at the species level.