Modern generation means modern modifications. Because of the exponential growth of population in the world, nonrenewable resources are at risk of being exhausted. Nonrenewable resources like coal, fossil fuels, and oil are gone once consumed and too much use of these resources may lead to different problems like global warming and depleting of ozone layer. Later, scientists have research ways to prevent exhaustion of these nonrenewable resources and one of which is producing bio ethanol from agricultural wastes.
Production of bio ethanol requires a high amount of sugar level. Ethanol is produced by microbial fermentation of this sugar. Currently, microbial fermentation only works directly with sugars like starch and cellulose which are the two major components of plants and can be converted to sugars for fermentation.
States that Republic Act No. 9367, also known as Biofuels Act of 2006, our country should reduce the dependence on imported fuels with due regard to the protection of public health, environment, and natural ecosystem with its sustainable economic growth. This Law aims to expand opportunities for livelihood by mandating the use of biofuels.
In terms of total production, rice is the third most important grain crop in the world. According International Rice Research Institute (IRRI) Rice Almanac (2013), the Philippines is the eighth-largest rice producer because of its arable land measuring 5.4 million hectares. This is because the Philippines is an agricultural country which mostly depends on crops. Despite of its large scale of arable land, the country was the biggest rice importer in 2010 and 2011 (IRRI Rice Almanac, 2013).
Varieties of rice have been cultivated and have been modified for better consumption of people. Because of its large numbers, scientists have researched what other products will the rice capable of producing; and later, they discovered that it could be rice wine, rice perfume, etc.
Rice wine has been loved by Filipinos since then and the process of making it is not that different from the process of other wines. One of the common processes is the fermentation where you will subject yeast to the cooked rice and wait for several weeks until the bubbles have subsided. When filtered, rice wine will yield into two different products, the lees and the juice.
Simultaneous fermentation process employs thermotolerant yeast strains to reduce the number of reactors involved by eliminating the separate reactor and more importantly, avoiding the problem of product elimination associated with enzymes such as build-up of cellobiase and amyloglucosidase which shut down starch degradation (Chandal et al. 2007). However, in SSF, both saccharifying enzyme and fermenting microbes are applied simultaneously. As the conversion of starch into sugars is processed by amlyoglucosidase, the fermentative organisms convert them into ethanol (Ward et al. 2002)
Lees still has this sweet taste after fermentation and is believed that is capable of producing bio ethanol. This study will be conducted to know whether lees is capable of producing bio ethanol when subjected by a bacteria known as Bacillus amyloliquefaciens. Simultaneous fermentation process will be done to verify whether lees subjected to B. amyloliquefaciens has high cellulose content needed to produce an ethanol.