Development of immobilized novel fungal consortium for the efficient remediation of cyanide-contaminated wastewaters

Free cyanide is a hazardous pollutant released from steel industries. Environmentally-safe remediation of cyanide-contaminated wastewater is required. In this work, Pseudomonas stutzeri (ASNBRI_B12), Trichoderma longibrachiatum (ASNBRI_F9), Trichoderma saturnisporum (ASNBRI_F10) and Trichoderma citrinoviride (ASN-BRI_F14) were isolated from blast-furnace wastewater and activated-sludge by enrichment culture. Elevated microbial growth, rhodanese activity (82 %) and GSSG (128 %) were observed with 20 mg-CN L-1. Cyanide degradation > 99 % on 3rd d as evaluated through ion chromatography, followed by first-order kinetics (r2 = 0.94-0.99). Cyanide degradation in wastewater (20 mg-CN L-1, pH 6.5) was studied in ASNBRI_F10 and ASN-BRI_F14 which displayed increased biomass to 49.7 % and 21.6 % respectively. Maximum cyanide degradation of 99.9 % in 48 h was shown by an immobilized consortium of ASNBRI_F10 and ASNBRI_F14. FTIR analysis revealed that cyanide treatment alters functional groups on microbial cell walls. The novel consortium of T. saturnisporum-T. citrinoviride in the form of immobilized culture can be employed to treat cyanide -contaminated wastewater.

Automated summary

Free cyanide, a hazardous pollutant released from steel industries, can be remediated using a consortium of Trichoderma saturnisporum and Trichoderma citrinoviride. These microorganisms displayed increased growth and degradation activity in the presence of 20 mg-CN L-1, with degradation rates of over 99% within 3 days. FTIR analysis showed changes in functional groups on microbial cell walls after cyanide treatment.