ICAR Research Data Repository for Knowledge Management
Simultaneous saccharification and co-fermentation of paddy straw for ethanol production
KrishiKosh
View Archive Info| Field | Value | |
| Title |
Simultaneous saccharification and co-fermentation of paddy straw for ethanol production
|
|
| Creator |
Goel, Annu
|
|
| Contributor |
Leela Wati
|
|
| Subject |
Ethanol, Paddy Straw, Fermentation, Saccharomyces Cerevisiae
|
|
| Description |
Contemporary industrial developments and rapid pace of urbanization have called for environmentally sustainable energy sources. Ethanol made from biomass can be considered as a safe and cleanest liquid fuel alternative to fossil fuels. Ethanol is economically produced from sugarcane and corn in Brazil and America, respectively. However, in a developing country like India with second largest population to feed and more than 200 million people living below poverty line sparing food crops for fuel ethanol production is not an option. Therefore, the priority in global future ethanol production is on lignocellulosic processing. Paddy straw is one of the most abundant lignocellulosic wastes on earth. Ethanol production from paddy straw is a three step process involving pretreatment, hydrolysis and fermentation. Ethanol production by separate hydrolysis and fermentation (SHF) enables enzymes to operate at higher temperature and fermenting yeasts at moderate temperatures, optimizing the utilization of sugars but to find economic acceptance, the cost for bioconversion must be lowered down and, for this, the most important process improvement made is the introduction of simultaneous saccharification and fermentation (SSF), which has further been improved to include the co-fermentation of multiple sugar substrates i.e., SSCF. Paddy straw (Pusa-1 variety) contained 35.07% cellulose, 24.85% hemicellulose, 6.29% lignin, 49.82% organic carbon and 0.85% nitrogen on dry weight basis. Alkali treatment of straw (mesh size 0.5mm) resulted in 70% lignin removal along with 88% cellulose recovery. Hydrolysis of pretreated paddy straw with commercial cellulase loaded @ 7.5 FPU/ g resulted in 75% saccharification with the release of 61% reducing sugars after 2 h of incubation at 50C. Hydrolysate supplemented with yeast nutrients (0.3% urea, 0.15% sodium dihydrogen phosphate and 0.5% yeast extract) inoculated with the co-culture of Saccharomyces cerevisiae and Pachysolen tannophilus resulted in production of 283 ml ethanol per kg delignified paddy straw at 35C after 72 h fermentation by SHF. Simultaneous accharification and co-fermentation of paddy straw supplemented with urea @ 0.3% resulted in production of 310 ml ethanol per kg delignified paddy straw with the co -culture of S. cerevisiae and P. tannophilus that was about 10 % higher than SHF. Sugar profile of hydrolysate after fermentation revealed xylose as nutilized sugar. Ethanol production efficiency in SSCF of paddy straw scaled up to 5 L capacity under optimized conditions was about 56%. The fermented residue was found to contain about 14% cellulose, 2.6% nitrogen and about 50 % residual enzyme activity. Cost of ethanol production by SSCF was lower compared to SHF in view of need of only one instrument, supplementation of cheaper yeast nutrients and without the need of buffering. |
|
| Date |
2016-08-08T11:48:55Z
2016-08-08T11:48:55Z 2012 |
|
| Type |
Thesis
|
|
| Identifier |
http://krishikosh.egranth.ac.in/handle/1/71467
|
|
| Language |
en
|
|
| Format |
application/pdf
|
|
| Publisher |
CCSHAU
|
|