Use of Monascus sp. NP1 for bioethanol production from Cladophora glomerata

Abstract

The fungus Monascus sp. was able to produce ethanol instead of red pigment under glucose derepression with greater and more tolerance to ethanol than yeast. Algae are known as a polysaccharide resource for bioethanol production. This work was focused on the optimization of cellulase production through solid-state fermentation of straw and rice bran using Trichoderma viride TISTR 3161 for saccharification by the alga, Cladophora glomerata. The best conditions for alga enzymatic hydrolysis were proposed after varying crude enzyme and temperature, comparing the enzyme method to the physical method of saccharification from the alga, characterizing bioethanol production from the fungi at the laboratory scale, and scaling up to a 10-L fermenter, and fermentation of the algal extract at a variety of pH at the laboratory scale. Cellulase production from Sangyod Phatthalung rice using 21.19-mg crude enzyme at 35 °C provided the best conditions of all five varieties of Thai rice tested in terms of producing reducing sugar via algal hydrolysis. This method obtained nearly the same amount of reducing sugar as the physical method (acid and high temperature). At the laboratory scale, 20% glucose in liquid medium was the best condition for ethanol production (1384 μM) of all glucose concentrations tested (2, 10, 20, 30, and 50%) at room temperature on a rotary shaker (110 rpm) for 120 h. The time of production could be reduced to 72 h to produce the same amount of ethanol in a fermenter. The pH of 6 was the proper condition for bioethanol production in algal extract media. The promise of this technique for bioethanol production was shown.