Rice Flour and White Glutinous Rice Flour for Use on Immobilization of Yeast Cell in Ethanol Production

Ethanol is a potential industrial chemical as a very promising biofuel to replace fossil fuels. Its capability to increase octane number and improve the emissions quality of gasoline drives the researches in efficient ethanol production. A rapid fermentation leading to high ethanol concentration; therefore a yeast strain with a good specific ethanol production rate becomes the main consideration. Due to several advantages presenting by the using of cell immobilization, such as increased productivity, reduced risk of contamination, biocatalyst recycling, rapid product separation and others, the interest of cell immobilization for ethanol production has increased in the last decades. The great importance to find cheap, abundant, and non-destructive immobilization supports, rice flour and white glutinous rice flour were tested as support for yeast immobilization in the present work. Three commercial yeast strains were used in the experiments, labelled A, B, and C. The fermentation runs were carried out with glucose as substrate in 250 mL Erlenmeyer flask containing 100 mL of medium and 5% of immobilized enzyme loading and statically incubated at 32oC for 72 hours. Fermentations were carried out in duplicate and fermentations under the same conditions described above were also performed without support addition for comparison. The results showed that white glutinous rice flour was great potential for use as immobilization support during the ethanol production by the C yeast strain culture.