Isolation and identification of bacteria from rotary drum compost of water hyacinth

Abstract Purpose The present work aims to isolate and identify bacterial community from the rotary drum compost of green waste such as the water hyacinth. Compost quality was also investigated with the physicochemical parameters and the heavy metal analysis. Methods For rotary drum composting, a waste mixture of 150 kg with water hyacinth, cow dung and sawdust were prepared in the proportion of 6:3:1, respectively. The physicochemical parameters such as pH, temperature, volatile solids and the electrical conductivity were analyzed to detect the compost quality. Pb, Ni, Zn, and Cd were investigated for total heavy metals, toxicity characteristic leaching procedure (TCLP), diethylenetriaminepentaacetic acid (DTPA) and water solubility tests. Consistent and active bacterial community were isolated from the rotary drum compost of water hyacinth. Culture-dependent and culture-independent techniques were approached for the isolation process. Results Twelve bacteria were isolated and identified by 16S rDNA sequencing and phylogenetic analysis; they majorly belonged to the Bacillus and Enterobacter family. The analysis of temperature, pH, EC, VS and heavy metals depicted the good quality of compost. Heavy metals concentration was in Pb > Ni > Zn > Cd; however, for Pb, Cd and Ni water solubility remained non-detectable, DTPA concentration for Pb and Cd was also found to be non-detectable. Conclusions The microbes in water hyacinth compost are metabolically active degrading the organic matter, surviving in the heavy metal-loaded compost environment. Thus, green waste (water hyacinth) can be utilized to isolate bacterial species in anticipation of their application in heavy metal removal in liquid and solid waste sources for micro-bioremediation