Utilization of damaged and spoiled wheat grains for bioethanol production

Abstract

First generation ethanol from starchy crops particularly maize is an established technology that being a renewable and bio-based resource has advantages over gasoline. The second generation ethanol from lignocellulosics owing to its economic considerations is still at pilot scale and is yet to see commercialization. This has increased the demand of starchy feed-stocks for energy. The recently released National Policy on Biofuels in May, 2018 categorically also emphasizes on the potential of different raw materials for ethanol production by consenting the utilization of damaged food grains like wheat, broken rice etc. that area otherwise unfit for human consumption. As far as wheat is concerned, The Comptroller and Auditor General (CAG), India (2017) reported that Food Corporation of India's (FCI) wheat stock worth 700 crores was damaged solely in Punjab from 2011 to 2016 as the grain was kept in open areas attributed to the lack in storage facility. Development of efficient technology to pretreat and convert damaged starch into fermentable sugars and optimization of enzymatic hydrolysis using commercial as well as indigenous enzyme preparation are the key points for the efficient bioethanol production from damaged wheat. Further, the synergistic action of alpha and glucoamylase in the hydrolysis of wheat mash have been tried that has revealed 96.25% conversion efficiency with an ethanol yield 5.60 % (v/v). The present review discusses research progress in bioethanol production from damaged wheat grains containing higher starch content. Thus, utilization of especially damaged and spoiled wheat grains pave better way for commercialization of bioethanol production from an economical perspective.