Evaluating the Role of Ultrasonication-Assisted Alkali Pretreatment and Enzymatic Hydrolysis on Cellwall Polysaccharides of Pennisetum Grass Varieties as Potential Biofuel Feedstock

摘要

Production of renewable fuel like bioethanol from plant biomass and agro wastes will be the future energy source to combat the depletion of fossil fuels. The first detailed profile of the non-cellulosic cell wall polysaccharides of native, ultra- sonication assisted alkaline (NaOH) pre-treated and enzyme hydrolysed Pennesitum grass varieties viz. hybrid Napier grass and denanath grass, were identified using glycome profiling. The best pre-treatment conditions resulted in 89.3% and 86.7% delignification of denanath grass (DG) and hybrid Napier grass (HNG) respectively. In the same conditions, 227.2 mg/g and 242.8 mg/g of total reducing sugar was achieved for DG and HNG respectively. Comparative assessment of a new enzyme i.e. Palkonal MBW with the conventional combination of Celluclast 1.5 L+ xylanase was undertaken. The amounts of glucose and xylose released with Palkonal MBW saccharified DG and HNG were 662.0 mg/g and 431.2 mg/g, which were significantly higher as compared to the conventional enzyme cocktail. The glycome profiling results showed that pectic arabinoxylan and arabinogalactan backbones were significantly less in DG samples and they do play a major role in enhancing enzymatic hydrolysis. These reports can provide a good insight in designing potential perennial feedstocks for bioethanol production in bio refinery concepts. Furthermore, the underu- tilised DG variety may also be exploited owing to its promising cell wall characteristics that can produce higher bioethanol yields.