چكيده به لاتين
Abstract
With the growth of population in the last decade, rising petroleum price and global warming, the attention has highly shifted to the renewable fuels which are compatible with the environment. Bioethanol as a cheap substitute of fossil fuels with utilization of lignocellulosic material has been taken into consideration recently. With reference to lignocellulosic substrate, bioethanol production can be produced by solid state fermentation (SSF) using appropriate pretreatment method. In this research, Bioethanol production from date pit powder with Zymomonas mobilis by SSF has been studied in the flask scale for the first time. Appropriate alkaline and alkaline–acidic pretreatments for SSF has been carried out to increase accessibility of microorganism to the available sugar of date pit powder. A factorial design with two factors of moisture and peptone with two levels were conducted to enhance yield of bioethanol production using alkaline–acidic pretreated date pit powder. Results show that both factors were significant in improving bioethanol production. The following situation has been obtained as an optimal point for SSF in a flask scale: initial substrate pH 5, initial substrate moisture of 50 %, particle size of 0.297-1.19 mm, peptone content of 0.085 g peptone g-1 dry substrate, yeast extract concentration of 10 g/l, temperature 30 °C and 60 h fermentation time. In this situation, maximum bioethanol production after 60 h of fermentation was 0.204 g ethanol g-1 initial sugar.
Keywords: Bioethanol, Date Pit powder, Solid State Fermentation, Zymomonas mobilis, Chemical Pretreatment, Lignocellulosic Substrate
