ABSTRACT
In view of raising prices of crude oil and due to increasing demands the need for alternative sources of bioenergy is expected to increase sharply in the coming years. Cajanus cajan Stalks is the major agricultural residue, more than 25% primary energy demands met through imports mainly in the form of crude oil and natural gas. Biofuels as a domestic renewable energy source can significantly reduce India’s dependence on foreign oil and fossil fuels. The Plant cell wall is a composite material in which cellulose, hemicelluloses & lignin are closely associated. The major constraint in successful bioconversion process is the lignin. The study was conducted for various pretreatment methods. The best is the steam pretreatment method. This method serves as best and effective pretreatment with the maximum removal of lignin and isolation of more reducing sugars and less pentose’s. The alkaline method specially NaOH treatment is used for extraction of more pentose’s in crude extract. Finally, our approach was to find out the best pretreatment method that result in release of maximum reducing sugars. Steam pretreatment serves to be best followed by saccharification by cellulose. Further, these fermentable sugars can be utilized for bioethanol production. Cajanus cajan stalk is mostly cultivated in Kalaburagi district of Karnataka for that can be used for ethanol production. Screening for isolation of S. cereviceae was carried out by using baker’s yeast and was grown in YPD media. The optimization of culture condition was carried out for growth of yeast showed optimum temperature at 30 ºC and optimum pH at 5. Optimum Cellulase enzyme activity was found to be at temperature 40 ºC and pH 4.5. The ethanol production reaction was optimized by the maximum utilization of sugars by yeast was optimized by providing hexose and with combination of xylose at temperature 30 ºC and pH 5.0 and the inoculum size was optimized at 5% volume of total volume for SSF. From the above results, it is clear that the cellulase enzyme isolated from Aspergillus niger has ability to grow and produce hexoses under conditions of optimum temperature and acidic pH. The reducing sugar and pentose’s both can be used together for ethanol production. The obtained reducing sugar and pentose’s sugar conc. were 1.025 gm/500 ml & 0.5 gm/500 ml. This is only possible by using biological enzymatic pretreatment. The resultant substrate can used for making 2-3% ethanol. Thus fermentable sugars by these methods can be utilized for bioethanol production. The ethanol produced from this agro waste is 2-3% in lab scale. Then go for pilot scale 4-5% and later for industrial scale 7-8% by treat with different pretreatment methods using SSF. This helps in increases the utilization of wastes for economic use and improves the biofuel production resources.
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