A low-cost and sustainable approach to microbial pectinase production from fruit processing wastes: from peel to profit

Microbial pectinases are one among the crucial industrial enzymes widely used in fruit juice clarification, textile processing, dietary fibre extraction and waste management. However, high cost of commercial raw materials poses a significant challenge in the microbial production of pectinases. The utilization of agro-food residues as low-cost substrates offers a cost-effective and greener approach to enzyme production. In this study, pectinolytic bacterial and fungal isolates were obtained from rotten fruits and vegetables; and screened for polygalacturonase and pectin lyase production. After characterizing the isolates for their ability to utilize various sugars, several agro-residues were evaluated as carbon and nitrogen substrates for pectinase production. <i>Fusarium annulatum</i> MIB02 exhibited significant polygalacturonase (155.23 IU mL⁻¹) with sweet lime peel powder and corn steep liquor as carbon and nitrogen substrates. Similarly, <i>Bacillus subtilis</i> MIPe01 demonstrated pectin lyase activity of 9.12 IU mL⁻¹ with orange peel powder and soybean meal. Although enzyme yield was lower from agro-residues compared to commercial pectin, potential trade-off between reduced production costs and production efficiency enhances the economic feasibility of pectinase production. The findings from our study support the valorization of agro-food residues as a greener and cheaper approach for pectinase production contributing towards a circular bio-economy.