Biosorption potential and molecular characterization of metal resistant autochthonous microbes from tannery solid waste

Abstract

This study encompasses isolation and screening of heavy metal-resistant fungal and bacterial strains from tannery solid waste (TSW). Twelve fungal strains and twenty-five bacterial strains were isolated from TSW. The growth of fungal strains was observed against different heavy metals ranging from 10 mg L-1 to 1050 mg L-1 and the growth of bacteria was observed in metal concentrations ranging from 10 mg L-1 to 1200 mg L-1. Five multi-metal resistant fungal isolates belonging to the genus Trichoderma and ten bacterial isolates belonging to the genus Bacillus showed good metal resistance and biosorption potential. They were identified through molecular techniques, fungi based on ITS region ribotyping, and bacteria based on 16S rRNA ribotyping. The fungal strains were characterized as T. hamatum (TSWF-06), T. harzianum (TSWF-11), T. lixii (TSWF-02) and T. pseudokoningii (TSWF-03, TSWF-10). The bacterial strains were characterized as Bacillus xiamenensis (TSW-02), B. velezensis (TSW-05), B. piscis (TSW-06), B. safensis (TSW-10), B. subtilis (TSW-14, TSW-15, TSW-17) B. licheniformis (TSW-19), B. cereus (TSW-20) and B. thuringiensis (TSW-22). The fungal strains namely, T. pseudokoningii (TSWF-03) and T. harzianum proved to be two multi-metal resistant strains with good biosorption efficiency. Unlike fungi, bacterial strains showed metal specific resistance. The strains Bacillus xiamenensis, B. subtilis (TSW-14) and B. subtilis (TSW-15) showed good biosorption efficiency against Cr, B. safensis against Cu, B. piscis and B. subtilis (TSW-17) against Pb and B. licheniformis and B. thuringiensis against Zn. The autochthonous fungal and bacterial strains can therefore be employed to clean metal contaminated environments.

Finding the best combination of autochthonous microorganisms with the most effective biosorption ability for heavy metals removal from wastewater

“…A contaminated environment has decreased variety while increasing the “richness” of select groups that have adapted to living in the presence of contaminants ( Roling et al, 2002 ). Among these creatures, microorganisms and certain fungi predominate ( Dusengemungu et al, 2020 ; Younas et al, 2021 ). Because of the large number of HM pollutants prevalent in the environment and the availability of many different types of microorganisms, it is not unexpected that efforts are being made to isolate and identify strains from polluted settings that might be utilized for HM bioremediation by diverse mechanisms at extracellular and intracellular levels.…”