Bioethanol, as a clean and renewable fuel, is considered as good alternative to replace fossil fuels. Bioethanol can be produced from a variety of feedstocks including sugar-, starch-, and lignocellulosic-based materials. Rice straw is one of the most abundant agricultural wastes in the world. In the present work, bioethanol production from rice straw by different morphologies of Mucor hiemalis was studied. The rice straw was treated with sodium hydroxide and phosphoric acid, with or without ultrasonication, prior to enzymatic hydrolysis. The alkali pretreatment was performed with 12% sodium hydroxide solution at 0°C for 3 hours; while phosphoric acid pretreatment was carried out at 50°C for 30 minutes. The pretreatments resulted in improvement of the enzymatic hydrolysis and the glucose theoretical yield of 76–93% was obtained.The best hydrolysis performance was achieved by ultrasonic-assisted sodium hydroxide pretreatment (93% glucose theoretical yield). The dimorphic fungus M. hiemalis is a dimorphic fungi which belongs to the kashida; TEXT-ALIGN: justify; LINE-HEIGHT: 17pt; TEXT-KASHIDA: 0%; TEXT-INDENT: 0cm; MARGIN: 0cm 0cm 0pt; unicode-bidi: embed; DIRECTION: ltr; mso-line-height-rule: exactly" Keywords: Chitosan, Ethanol, Morphology, Mucor hiemalis ,Phosphoric acid, Pretreatment, Rice straw, Sodium hydroxide.
