چكيده به لاتين
The most common biofuel used in the world is bioethanol, one of the most suitable sources of its production is agricultural waste that has been studied for over three decades. Due to the high production and consumption of dates in the country and the region, kernels are one of the largest potential sources of lignocellulose available for bioethanol production. In this study, bioethanol production from kernel powder was investigated using Zymomonas mobilis by solid state fermentation method and pichia stipitis by semi-solid state fermentation method at flask scale. In order to allow microorganism access to five and six carbon dioxide carbohydrates, the optimum conditions of pre-treatment of 1 M alkaline and acid hydrolysis with 5% sulfuric acid were determined. As a first step, production of bioethanol by solid-state fermentation in 50 ml Erlens using peptone as nitrogen source at 0.1 and 0.2 g/g initial dry hydrolyzed substrate (IDHS) at 30 °C and 50% moisture pretreatment substrate was examined for 3 days. Due to the low production efficiency in the next step, the effect of adding four nitrogen sources of peptone (0.1, 0.2 and 0.3 g peptone/gIDHS), wheat bran (40, 50 and 60 % of initial dry substrate weight) and sulfate ammonium (0.01, 0.02 and 0.04 g (NH4) 2SO4/gIDHS) in three levels and dried yeast (0.07 and 0.14 gDSY/gIDHS) in two levels on bioethanol production by semi-solid state fermentation method. The half-life was evaluated in 100 ml Erlens wells at 30 °C and 150 rpm for 3 days. The maximum bioethanol production in each nitrogen source was 0.09, 0.1, 0.07 and 0.09 g of ethanol per gram of IDHS, respectively.
