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1、New York Science Journal 2010, http:/ 72Production of Bioethanol Via Enzymatic Saccharification of Rice Straw by Cellulase Produced by Trichoderma Reesei Under Solid State Fermentation Fatma, H. Abd El-Zaher1* and Fadel, M2 1 Department of Agricultural Microbiology, National Research Center, Cairo,
2、 Egypt. Post. Address 12622. 2 Department of Microbial Chemistry, National Research Center, Cairo, Egypt. Fatimaom_ Abstract: Alternative substrates to produce useful chemicals such as biofuel have been attractive. Rice straw, one of the most abundant lignocellulosic wastes by-products world wide ca
3、n be used for this purpose. In the present study the production of cellulase by Trichoderma reesei F-418 cultivated on alkali treated rice straw using solid state fermentation (SSF) technique. The high cellulase activity was obtained when the fungus was cultivated on substrate with about 75 % (v/w)
4、moisture, pH 4.8 for 5 days incubation at 282C, as it gave 16.2 IU/g substrate. The obtained cellulase of 1.2 IU/ ml culture filtrate was applied for saccharification (5% w/v) of alkali treated rice straw, in 0.1M citrate buffer pH 4.8 in shaker water bath of 100 rpm. Sugary solution of 1.07 % gluco
5、se was achieved after 16 hrs. The sugary solution was concentrated to give 10% (w/v) glucose. Ethanolic fermentation was conducted by Saccharomyces cerevisiae SHF-5 under static condition giving 5.1% (v/v) ethanol after 24 hrs. The fermented mash contained 3.6 g/L yeast cell can be utilized as foode
6、r yeast used for animal feeding. New York Science Journal. 2010;3(4):72-78. (ISSN: 1554-0200) Key words: rice straw, Trichoderma reesei F-418, cellulases, fermentation, biofuel. 1. Introduction Nowadays, alcohol fuels have been produced on industrial scales by fermentation of sugars derived from whe
7、at, corn, sugar beets, sugar cane etc.The enzymatic hydrolysis of cellulosic materials to produce fermentable sugars has an enormous potential in meeting global bioenergy demand through the biorefinery concept, since agri- food processes generate millions of tones of waste each year (Xeros and Chris
8、takopoulos 2009) such as sugar cane baggase , wheat straw and rice straw. In fact rice straw (RS) is one of the most abundant lignocellulosic wastes by-products world wide and provides an alternative substrate to produce useful chemicals such as biofuel (Yao et al., 2007). RS has traditionally been
9、dried and burned in the fields reducing the local air quality considerably, this have directed a world wide attention to wards utilization of RS for bioethanol. It contains between 25-45 % of cellulose, 20- 30 % hemicellulose and 10-15 % lignin (Sun and Cheng., 2002). Cellulose is degraded by enzyme
10、s known as cellulases that are able to hydrolyse the cellulose polymer to its monomer, the sugar glucose, that is naturally fermented to ethanol by the yeast Saccharomyces cervisiae. Fungi are able to degrade cellulose, hemicellulose and lignin in decaying plants by a complex set of excreted hydroly
11、tic and oxidative enzymes (Gosh and Gosh, 1992). Lignocellulose degrading organisms have been used for the conversion of lignocellulosic materials into soluble sugars or solvents in several biotechnological and industrial applications (Gomes et al., 2006). Current technology for conversion of lignoc
12、ellulose to ethanol requires chemical or enzymatic conversion of the substrate to fermentable sugars followed by fermentation by a microorganism. The large amounts of enzymes required for enzymatic conversion of hemicelluloses and cellulose to fermentable sugars impacts severely on the cost effectiv
13、eness of this technology (Xeros and Christakopoulos 2009). The physical support and the energy required for a fungus to grow and produce the desired metabolite is primarily provided by a substrate (Pandy et al., 2001). Considerable research efforts have been made to improve conversion yields of lign
14、ocellulosic materials by the insertion of a pre-treatment step prior to the enzymatic hydrolysis. Dilute NaOH is an effective pre-treatment for lignocellulosic materials with relatively low lignin content of 10 to 18% (Bjerre et al., 1996). A large variety of microorganisms are capable of degrading
15、plant cell wall materials (Carle- Urioste et al., 1997 and Acebal et al., 1986). It was reported by many authors that Trichoderma reesei is capable of increase the production of cellulase from substrate like corn straw and similar others. T. reesei can be chosen as model fungus as it shows both the challenging rheology and a cellulase complex product that is shear- sensitive ( Weber and Agblevor , 2005). T. reesei is the most extensively studied and it has served as a model for fungal lignoellulo
