SPENT SUBSTRATE FROM MUSHROOM INDUSTRY, A POTENTAIL DYE DECOLOURIZING AGENT

Dye decolourization using spent mushroom substrate (SMS) is influenced by the category of SMS, type of dye, initial dye concentration, form of mushroom mycelia, pH, temperature and the growing media. Among SMS of different mushrooms, the SMS from P. sajor-caju exhibited highest population along with variability of both fungi and bacteria. Five fungi viz., Aspergillus fumigatus, Paecilomyces variotii, Pichia guilliermondii, Schizophyllum commune and Pezizomycotina sp. with potential dye decolourization potential have been recorded to thrive on SMS of different mushrooms by using 5.8S rRNA gene sequencing and BLASTn techniques. Out of these Schizophyllum commune from P. sajor-caju SMS has been recorded to exhibit highest decolourization potential (95%) with in 10 days against Chicago sky blue. This fungus also exhibited dye decolourization potential of 100, 92.50, 81.60, 73.40 and 67.80% against other dyes like Starch Azure, Reactive blue, Rhodamine B, Orange II sodium salt and Methyl blue, respectively. Similarly, by using 16S rRNA gene sequencing and BLASTn, six potential bacteria viz., Bacillus subtilis, B. pumilus, B. licheniformis, Pseudomonas fluorescens, Sphingobacterium multivorum and Rummelibacillus stabekissi have also been identified, out of which B. licheniformis isolated from P. sajor-caju SMS, exhibited highest decolourization potential of 66.10% against Orange II sodium salt, followed by Bacillus pumilus (57.7%). Temperature and pH optima of 25oC and 6.0 respectively, have been recorded for achieving highest level of decolourization through B. licheniformis. The study highlights the utility of SMS for unconventional activities like dye decolourization, which indirectly supports its use in bioremediation activities.