RSM approach to pre-treatment of lignocellulosic waste and a statistical methodology for optimizing bioethanol production

A potential substitute for a sustainable and long-term energy source is bioethanol. Although converting lignocellulose to bioethanol may be more economical, eco-friendly, and effective, it would still require extensive process-development and improvement to make biofuel economically feasible. An essential stage in the production of bioethanol is the pre-treatment of biomass to dissolve lignin and recover holocellulose. In this study, waste biomass from agro-forestry was converted into bioethanol by using various pre-treatments and selecting the one that produced the best results to optimize the process using the Classical One Factor at a Time approach (COFAT). The saccharification of selected biomass was done using in-house cultures of hyper-cellulase (Bacillus stratosphericus N12) and hyper-xylanase (B. altitudinus Kd1) producers, while the yeast cultures for fermentation of biomass i.e. Streptomyces cerevisiae and Pichia stiptis were purchased as sterile cultures. COFAT used inoculum size, fermentation pH, incubation time and temperature as optimization parameters and each of these increased the amount of bioethanol produced. Additionally, the Central Composite Design (CCD) of Response Surface Methodology (RSM) contributed to the 28.44 g/L maximum bioethanol output. The pre-treatments that separated the lignin from the holocellulose allowed it to be used in another investigation for the manufacture of nanoparticles and as a biocontrol agent. Since each component of waste biomass can be used to make useful products such as bioethanol from holocellulose and an anti-fungal biocontrol agent from lignin, a comprehensive approach to bioutilization of lignocellulosic biomass has been undertaken.