Fungi help make biofuel from rice husk
doi:10.1038/nindia.2016.8 Published online 21 January 2016
By using a specific fungus, researchers have synthesized biofuel from rice husk cellulose1. The fungus converted glucose derived from cellulose into the biofuel ethanol, which is potentially useful for reducing the emission of greenhouse gases caused by the burning of fossil fuels.
Burning fossil fuels produces greenhouse gases that contribute to global warming. In addition, global fossil fuel reserves are fast depleting, exacerbating the need to develop renewable energy sources such as biofuels.
To make the biofuel, the researchers isolated cellulose from ground rice husk by treating it with alcohol and lithium hydroxide solution. They then synthesized glucose from rice husk cellulose through acid hydrolysis. Finally, they used a novel fungal strain (Myrothecium gramineum) isolated from acacia trees to convert the glucose into ethanol.
Sulphuric acid treatment at 140 degrees Celsius for an hour converted cellulose into glucose with a yield of 60 per cent. This yield was considerably higher than that (25 per cent) obtained using another fungal strain, known as Aspergillus niger.
The isolation of cellulose, the conversion of cellulose into glucose, and the use of the renewable fungus to convert glucose into ethanol provide a promising opportunity to utilize agricultural wastes such as rice husk, the researchers say.
1. Das, A. M. et al. Extraction of cellulose from agricultural waste using MontmorilloniteK-10/LiOH and its conversion to renewable energy: biofuel by using Myrothecium gramineum. Carbohydr. Polymer. 141, 20-27 (2016)