Optimization and Modeling of Alkali Pretreatment using Response surface methodology for Bioethanol Production from Guinea grass (Panicum maxicum)

Abstract:

In the present demand for renewable and sustainable sources of energy to overcome the burden on world energy crisis, perrenial grasses have presented exciting options. Panicum maximum (Guinea grass) is a perennial grass and can be utilized for the production of bio-fuel in the form of cellulosic ethanol as it is a cost effective and efficient feedstock for bioethanol production. The conversion of biomass into glucose, an important step for the bioethanol production and it requires optimum pretreatment. Among various pretreatment methods available, alkali treatment reduces the lignin content and decreases the crystallinity of cellulose efficiently. In the present paper Response surface methodology was applied to optimize the alkali pretreatment of P.maximum (Guinea grass) for maximum reducing sugar production. Joint effects of five independent variables; Sodium Hydroxide concentration (0.5-3%), Temperature (40-150 ºC), Substrate loading (0.5-2%), pH (9-13) and Reaction time (15-150 min), were investigated. The optimum conditions in which maximum reducing sugar yield obtained were: 1.8% substrate, 1% Sodium Hydroxide loading, 9.5 pH, a reaction time of 127.5 min, and a temperature of 110 ºC. This result has been statistically analyzed with a second order polynomial equation. Under this combined optimal condition, the desirable reducing sugar content in the sample increased from 37.72 to 57.42%. This study reveals the promising use of P.maximum biomass as a feedstock for getting reducing sugar,that is required for bioethanol production.

Keywords:  Response surface methodology, Feedstock, Biomass, Pretreatment