Biodegradation of print-ink effluent by indigenous microbial isolates

The discharge of untreated print-ink effluent in and around the residential and industrial areas constitutes major environmental and health hazards. Hence, a need for an adequate, effective, economical and environment-friendly treatment method. This study thus evaluates the biodegradation potential of indigenous microbial cells from an ink-effluent environment. Ink effluent and ink pigment samples were collected from the printing-ink industries. Microbial cells were isolated and identified using standard microbial analysis. Isolates were selected for their capability to degrade ink pigment and print ink effluent using agar well-incorporated ink pigments. Molecular analysis was carried out on potential print ink degraders and strains were deployed for degradation analysis, using the microbial cells along with their solid-state fermentation (SSF). Degradation analysis was monitored using a gas chromatography-mass spectrophotometer (GCMS). The results showed that Klebsiella and Aspergillus species were predominant among the nine genera of bacteria and two genera of fungi. Pseudomonas aeruginosa and Penicillium citrinum proved to be the tolerant and potential cells for degradation studies. GCMS analysis confirmed the degradation abilities of the potential strains by showing the disappearances of compounds and the formation of new metabolites after the microbial and SSF treatments. Conclusively, the degradation abilities of P. aeruginosa and P. citrinum demonstrated a remarkable potential to efficiently detoxify ink effluent for environmental safety.