Optimization of dilute acid and dilute base pretreatment of tropical sawmill dust for bioethanol production
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Date
APRIL, 2016
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Abstract
There is abundance of lignocellulose biomass in Ghana. Currently, there are a lot of sawmill factories and carpentry shops in the country. The use of sawmill dust for the production of bioethanol will go a long way to alleviate environmental pollution by the reduction in the mission of harmful gases which result by burning of these waste products. Most of these gases
lead to air pollution and can also contribute to the greenhouse effect. Using sawmill dust will also help minimize the use of land and foodstuffs for the generation of bio-energy. In this study, the optimum amount of glucose was determined by using different concentrations of dilute acids and bases for the pretreatment of different sawmill dust from two different plant species to
release glucose for bioethanol production. Concentrations of 0.25 M, 0.5 M and 1 M each of sodium hydroxide, ammonia, sulphuric acid and hydrochloric acid were used for the pretreatment of sawmill dust from Mahogany (Swietina macrophylla) and Kapok (Ceiba pentandra) plant species at different temperatures and resident times. The temperatures used for the sodium hydroxide and ammonia were 75°C, 90°C and 100°C at resident times of 30, 60 and 90 minutes and 121°C at resident times of 10, 15 and 20 minutes. The temperature used for both the sulphuric acid and hydrochloric acid was 121°C at resident times of 30, 60 and 90 minutes.
The optimum amount of glucose (3.37 g/l) for the base was achieved by the use of 1 M sodium hydroxide at 100°C for 90 minutes with Ceiba pentandra. The optimum amount of glucose (0.74 g/l) for the acid was attained by the use of 1 M hydrochloric acid at 121°C for 30 minutes with Mahogany plant species. The optimum amount of glucose (5.27 g/l) was attained by the use of
cellulase enzyme at 55°C for 30 minutes with Mahogany plant species. The highest amount of ethanol (3.48 x 10-2 % w/v) was attained by carrying out fermentation with Saccharomyces cerevisiae at a temperature of 50°C at a pH of 4.0 for 5 days. The use of high temperatures and concentrations produced higher glucose concentrations with the chemical pretreatments and hence provide an alternative way of producing bioethanol.
Description
A thesis submitted to the Department of Biochemistry and Biotechnology, College of Science in partial fulfilment of the requirements for the degree of
Master of Science in Biotechnology.