Ethanol production from lignocellulosic materials by fermentation process using yeast

V Bakare,B Benjamin,M.S Abdulsalami,B.C Onusiriuka,J Appah,T.O Ndibe

doi:10.4314/jasem.v23i5.17

Abstract

Rapid industrialization and growing population result to high demand for energy. Depletion and rise in price of petroleum as well as environmental pollution necessitates the need for alternative source of fuel, hence bioethanol production. Rice bran (Oryza sativa), Corn bran (Zea mays) and Sorghum bran (Sorghum guinense) and saw dusts of Khaya senegalensis (Red wood), Terminalia superba (Black wood), Gmelina arborea (White wood), were used for the study. The yeasts used for the study were isolated from fermented beverages (Sorghum beer, Millet beverage and Palm wine). The results of the lignocellulosic biomass of white saw dust, red saw dust, black saw dust, rice bran, corn bran and sorghum bran revealed cellulose components as 77.78%, 75.55%, 68.59%, 64.83%, 54.82% and 55.14% respectively. A total of 25 yeasts were isolates and identified using API 20C AUX strip. The yeast isolates, K2, B5, B7 and P1 had the highest ethanol tolerance value of 14%. The results showed that the ethanol-producing ability of the yeast isolates ranged from 4.1% to 10.3%. Fourier Transform Infrared Spectrophotometer (FTIR) and Gas Chromatography and Mass Spectrometry (GC-MS) analyses showed that ethanol is the main compound produced by yeasts from the lignocellulosic materials. This study revealed that Saccharomyces cerevisiae isolated from palm wine (P1) is best in ethanol production and tolerance, and this high prolific strain can be exploited or engineered for ethanol production. Therefore, Lignocellulosic biomasses are recommended as raw materials for producing ethanol, which is a promising alternative energy source as against the depleting petroleum.Keywords: Ethanol, Lignocellulose, Yeasts, Beverages and Saccharomyces cerevisiae.

Highlights

The demand for energy is increasing due to growing population and industrialization, implying that energy shortage will be a global problem in the nearest future
Proximate Composition and Total Carbohydrate Content of the Lignocellulosic Biomass: Proximate percentage values of dry matter (DM) in substrates are recorded as 96.60%, 96.12%, 95.86%, 95.09%, 93.73%, and 92.76% (Fig. 1)
Ethanol-Producing Ability of the Yeast Isolates: The results showed that the ethanol-producing ability of the yeast isolates ranged from 4.1% to 10.3% (Table 2)

Summary

Introduction

The demand for energy is increasing due to growing population and industrialization, implying that energy shortage will be a global problem in the nearest future. The use of ethanol in automobiles as an alternative fuel presents a viable option for improving energy security and reducing greenhouse emissions (Wyman, 1990). This has attracted worldwide attention to its production on a large scale while enhancing the economic status of a country (Cardona and Sanchez, 2007). Lignocelluloses in nature are derived from wood, grass, agricultural residues, forestry wastes and municipal solid wastes They consist of three major components of polymers: cellulose, hemicelluloses and lignin. The objective of the study was to produce ethanol from lignocellulosic materials by fermentation process using yeast

Objectives

Methods

Results

Conclusion