PRODUCTION OF THE BIOETHANOL FROM THE LIGNOCELLULOSIC AGRICULTURAL WASTES
Loading...
Date
2022
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
DRPCAU, PUSA
Abstract
Since the production of biofuels from renewable feedstocks and utilised as alternative fuels and sources of energy, recently they have attracted a lot of attention. Due to its favourable effects on the environment, bioethanol is one of the most intriguing fuels. Currently, it is mostly made from raw materials that comprise sugar and starch. The collected substrate delignified by the effective pre-treatment including the physical method (size reduction and the thermal treatment under the vapour pressure in the autoclave) and chemical treatment as 2% NaOH under the vapour pressure. The alkaline treatment combined with thermal treatment delignified the collected lignocellulosic substrates and released the reducing sugar by depolymerizing the cellulose and hemicellulose. The corn cobs were getting more hydrolyzed by the NaOH based pre-treatment by making maximum reducing sugar (38.908±0.27 mg gds-1) for fermentation among the four collected substrates. The pre-treated biomass saccharified by the bacterial and fungal consortium procured from the Department of Microbiology. The consortium of the 7 bacterial isolates (Bacillus sonorensis, Bacillus subtilis, Bacillus inaquosorum, Bacillus cabrialesii, Bacillus subtilis, Bacillus paramycoides and Bacillus stercoris) hydrolyzed the four substrates within 7-8 days of incubation. The maximum reducing sugar due to the hydrolysis by bacterial consortium resulted from the wheat straw (27.58±0.31 mg gds-1). The hydrolysis of the pre-treated four
substrates hydrolyzed by the fungal consortium of the three fungal isolates as Fusarium falciforme, Phanerochaete chrysosporium and Fusarium falicorme within 5-6 days of the incubation. The maximum reducing released from the corn cobs (35.43±0.16 mg gds-1) followed by the cane bagasse (35.174±0.44 mg gds-1). Biomass hydrolysis as fungal consortium followed by bacterial consortium hydrolysis of the pre-treated biomass, yielded maximum reducing sugar (45.602±0.43 mg gds-1) from the corn cobs among the other treatment of hydrolysis. The maximum hydrolysis of the corn cobs resulted maximum reducing sugar followed by paddy straw and cane bagasse. But considering the period required for getting maximum reducing sugars, hydrolysis by fungal and bacterial consortium combinedly was not efficient. The fermentation of the isolated hydrolysate containing reducing sugars done by yeasts Saccharomyces cerevisiae and Pichia stipitis. The yield estimation of the bioethanol from the distillate extracted by the distillation of fermented hydrolysate at 78.3ºC were ranging between the 1.762 to 3.763%. As the maximum reducing sugar released from the corn cobs during pre-treatment resulted maximum bioethanol yield (37.63±0.11 mg gds-1) with fungal followed by bacterial consortium saccharification among the four collected substrates. The least bioethanol yield was found from the paddy straw (17.623±0.118 mg gds-1).