PRODUCTION OF ETHANOL FROM CASSAVA (MANIHOT ESCULEUTA)
ABSTRACT
A literature review of ethanol production from local materials especially from cassava is presented. The study was carried out to investigate the production of a good quality ethanol from cassava using microorganisms. The micro- organisms used were malt and yeast (saccharomyces cerevisae). The other intermediate production was starch and sugar which ethanol was obtained in a satisfactory yield and purity (about 98%). It is therefore not 100% ethanol.
CHAPTER ONE
- INTRODUCTION
Ethanol is produced commercially by chemical synthesis and fermentation. Practically all industrials ethanol is manufactured synthetically from petroleum and natural gas while all beverage alcohol is produced by fermentation of cereal grains molasses, potatoes and other materials with high starch and sugar contents.
Potentials sources of production of alcohol in Nigeria include millet, yam, sorghum, corn, cocoyam and cassava. Cassava tuber (manihot esculenta) is the most potential candidate by virtue of the fact that this crop can be grown with low level of management and also varieties for industrials production and presence of high yielding cultivars.
Cassava (manihot esculenta) also called manioc of the spurge family (Euphorbiaceous) is native from South Africa but is now cultivated in most tropical and subtropical regions. It is a shrubby prennial about 9ft high and has terminal starchy tuberous root. The root contain prussic acid and some are quite poisonous but heat expels the volatile acid and render the materials harmless.
The hydrolysis of cassava and utilization of an efficient low cost saccharifying agent are factors of paramount importance in the production of food or alcohol from cassava starch since this polysaccharide must be broken down into fermentation sugar which can be utilized by the micro- organisms.
The amylolytic enzymes used in the biological saccharification can be obtained from several sources. These include COM, and barley malt and the surface and submerged fungal and bacteria culture processes.
The breakdown of geletimized starch occur via the hydrolysis of the – 1.4 linkages which from the glucose molecules and also via the hydrolysis of – 1,6 amylopectin component of starch. Malt contain the three most important enzymes for the starch breakdown – amylase. B – amylase and amyloglicosidase.
Ethanol (ethyl alcohol) is produced by the anaerobic fermentation of the saccharified starch (reducing sugar) by yeast via the embden – meyerhoff – parnas (EMP) pathway of anaerobic fermentation. Saccharomyces cerevisae was chosen for such characteristics as their ability to ferment rapidly and to tolerate higher ethanol concentration and to flocculate easily
