IDENTIFICATION OF NOVEL BACTERIAL STRAINS FOR ENHANCED HUMAN WASTE DEGRADATION

Abstract

Human excrement is a highly rich source of heterogeneous microbial flora that can be used in organic waste breakdown and environmental biotechnology. The objective of this study was to isolate, identify and test the extracellular enzymatic potential and consortium compatibility of bacterial strains from ten districts of Haryana, India on human fecal samples. Overall, 36 morphologically distinct bacterial isolates were isolated, with significant spatial variation in abundance and diversity. The number of isolates obtained from different localities of Jind district were maximum (7) followed by Rewari, Mahendargarh, Rohtak and Faridabad with 4 isolates each respectively, and the lowest number of isolates were found in Nuh and Kurukshetra with 2 isolates each respectively, indicating the effect of physicochemical conditions, organic load and sanitation level on the distribution of microorganisms in the area. There was a high level of functional differentiation among isolates as detected by enzymatic screening. The bacteria Bacillus cereus (NT-55) and Microbacterium paraoxydans (NT-11) were found to be effective multi-enzyme-producing bacteria, with a high level of peroxidase, laccase and amylase activities. Escherichia coli and Shigella sonnei had less peroxidase activity, with Klebsiella and Enterococcus exhibiting prominent enzyme activity. The use of molecular identification techniques (16S rRNA sequencing) revealed wide phylogenetic diversity among the bacteria, including a branch of Microbacterium paraoxydans (NT 11) within the phylum Actinobacteria that might indicate potential novelty. Compatibility assays performed with the consortium showed good synergism among the selected isolates of Bacillus sp., Enterobacter sp. and Acinetobacter sp. and there were no antagonistic reactions observed. This stable consortium of multiple enzymes had a cooperative growth, suggesting that it is able to degrade complex organic matter rapidly. The results underscore the promise of bacteria isolated from human excreta for creating new microbial communities that can speed up the degradation processes and aid waste management and environmental cleanup in a sustainable manner.