Laccase mediated delignification of pineapple leaf waste: an ecofriendly sustainable attempt towards valorization

Background: Escalating energy security, burgeoning population and rising costs of fossil fuels have focussed our attention on tapping renewable energy sources. As the utilization of food crops for biofuel production culminates into food vs. fuel dilemma, there is an intensive need for alternatives. Production of biofuels from lignocellulosic biomass owing to its profuse availability and high holocellulose content is a promising area for research. Results: In the present study, pineapple leaf, an agro-industrial waste was pretreated with laccase to enhance the enzymatic digestibility of the substrate for improved production of reducing sugar. Variables determining enzymatic delignification of pineapple leaf waste have been optimized by response surface methodology based on central composite design. Maximum delignification of 78.57%(w/w) resulted in reducing sugar of 492.3 +/- 33.1 mg/g in 5.30 h. The structural changes in pineapple leaf waste, after laccase treatment, were studied through Fourier transformed infrared spectroscopy, X-ray diffraction and Scanning electron microscopy. Specific surface area, pore volume, and pore diameter of the substrate were studied using the Brunauer-Emmett-Teller and Barrett-Joyner-Halenda methods and found a significant increase in the aforementioned parameters after delignification. Conclusion: Laccase mediated delignification of pineapple leaf waste is a cleaner sustainable process for enhanced production of reducing sugar which can accomplish the demand for biofuels.