Alcoholic fermentation of rice hulls hydrolyzed by rumen fluid obtained from slaughterhouse wastes

摘要

Increased awareness on climate change causing fossil fuels created a global movement to produce and use ethanol. As a result, several regulatory standards coupled with financial incentives which support the use of ethanol have been implemented in the past decade. However, the selling price of ethanol in the global market is still not competitive due to its high processing costs. In an attempt to reduce the market price of ethanol, we test the extent to which rumen fluid obtained from slaughterhouse wastes can effectively convert cellulose into glucose. The hydrolase collected was filtered to remove inactive rumen microorganisms and this was subsequently fermented into ethanol. Control experiments were also performed to also assess the fermentability of the unfiltered hydrolase. A semi-factorial experimental design was adopted to evaluate the influence of initial rumen fluid concentration, initial rice hull dosage, and contact time on the glucose yield. Factor interactions and its effects on the glucose yield were assessed through two-way ANOVA comparison of the experimental data. Results show that the rumen fluid effectively hydrolyzed the cellulose into glucose. Even though a higher ethanol yield was observed for the filtered hydrolase, significant ethanol concentration produced in the unfiltered hydrolase indicated minimal inhibition of ethanol fermentation activity in solution. These findings suggest the potential use of rumen fluid in producing fermentable carbohydrates for the production ethanol. Due to the voluminous generation of slaughterhouse wastes annually, rumen fluid can be an inexpensive alternative source of cellulolytic enzymes that are essential for fermentation of glucose into ethanol.