Production of thermostable recombinant cutinase using mixed food waste: A sustainable approach toward environmental remediation

Recently, there has been a significant surge in the utilization of single-use plastics. Cost-effective degradation of plastics is imperative to reduce the ecological burden. This study explores the overproduction and characterization of a PET (Polyethylene terephthalate) a degrading enzyme, cutinase, in the E. coli BL21 (DE3) expression system. Furthermore, this research delves into the utilization of mixed food waste (MFW) as a sustainable substrate for the production of Cutinase, replacing commercial glucose. The newly isolated strain, Aspergillus terreus, showed the highest glucoamylase activity of 76.10 +/- 3.10 U/g. The enzymatic hydrolysis of mixed food waste resulted in 50 +/- 0.4 g/L of glucose, used as feedstock for cutinase production. The crude enzyme activity was evaluated to be 11.64 U/mg, and a further 14.11-fold purification was achieved through IMAC. The purified recombinant enzyme showed its maximum activity at 70degree celsius and pH 7. The metal ion Na+ increased the enzyme activity by 26 % while Zn+2 significantly inhibited the same (47 % inhibition); other ions had little or no effect. Taguchi's optimization of five variables showed that the concentration of food waste hydrolysate has the maximum impact on enzyme production. The treatment of commercially available PET bottles using the purified enzyme showed characterizable surface degradation effects. This is the first time food waste hydrolysate was used as a sole carbon source to produce recombinant cutinase. This approach can potentially pave the way for sustainable biorefinery and waste management.