Ethanol production from sweet sorghum juice in repeated-batch fermentation by Saccharomyces cerevisiae immobilized on corncob

Abstract

Ethanol fermentation from sweet sorghum juice containing 240 g/l of total sugar by Saccharomyces cerevisiae TISTR 5048 and S. cerevisiae NP 01 immobilized on low-cost support materials, corncob pieces, was investigated. In batch fermentation, S. cerevisiae TISTR 5048 immobilized on 6 × 6 × 6 mm(3) corncobs gave higher ethanol production than those immobilized on 12 × 12 × 12 mm(3) corncobs in terms of ethanol concentration (P), yield (Y ( p/s )) and productivity (Q ( p )) with the values of 102.39 ± 1.11 g/l, 0.48 ± 0.01 and 2.13 ± 0.02 g/l h, respectively. In repeated-batch fermentation, the yeasts immobilized on the 6 × 6 × 6 mm(3) corncobs could be used at least eight successive cycles with the average P, Y ( p/s ) and Q ( p ) of 97.19 ± 5.02 g/l, 0.48 ± 0.02 and 2.02 ± 0.11 g/l h, respectively. Under the same immobilization and repeated-batch fermentation conditions, P (90.75 ± 3.05 g/l) and Q ( p ) (1.89 ± 0.06 g/l h) obtained from S. cerevisiae NP 01 were significantly lower than those from S. cerevisiae TISTR 5048 (P< 0.05), while Y ( p/s ) from both strains were not different. S. cerevisiae TISTR 5048 immobilized on the corncobs also gave significantly higher P, Y ( p/s ) and Q ( p ) than those immobilized on calcium alginate beads (P < 0.05).

Current Trends in Bioethanol Production by Saccharomyces cerevisiae: Substrate, Inhibitor Reduction, Growth Variables, Coculture, and Immobilization

“…On the other hand, since wastes are cheap, it reduces cost of ethanol production. Second, nonfood extracts from sweet sorghum [ 28 , 44 , 45 ] and cashew apple [ 31 ] have been used as a substrate for S. cerevisiae . The extracts are best suited for ethanol production under very high gravity technology since adequate sugars are obtained through the extraction compared to lignocellulose hydrolysis.…”

“…Alternatively, new immobilizing agents that are cheap and easy to use have been investigated in several studies ( Table 3 ). These include sugarcane bagasse [ 27 ], alginate-chitosan beads [ 32 , 74 ], corncob pieces [ 28 ], sweet sorghum pith [ 29 ], alginate-maize stem ground tissue matrix [ 33 ], cashew apple bagasse [ 31 ], lyophilized cellulose gel [ 34 ], dried spongy fruit of luffa ( Luffa cylindrica L.) [ 30 ], carboxymethylcellulose (CMC) grafted with N-vinyl-2-pyrrolidone [ 75 ], sodium alginate grafted with N-vinyl-2-pyrrolidone [ 35 ], Lentikat discs [ 38 ], and rice flour and white glutinous rice flour [ 76 ].…”

Life-cycle energy use and greenhouse gas emissions of production of bioethanol from sorghum in the United States

“…The yeast dosage for sugar-based ethanol production was estimated at 5.2 grams /kg substrate according to data from laboratory-scale studies [42-45]. The enzyme and yeast dosages for cellulosic ethanol production from FS were based on cellulosic ethanol production [46].…”

Bioethanol Production Using Saccharomyces cerevisiae with Different Perspectives: Substrates, Growth Variables, Inhibitor Reduction and Immobilization

“…Also, several studies have been done to investigate new immobilizing agents that are cheap and easy to use ( Table 2). Yeast immobilization enhances ethanol productivity because-a) it reduces risk of contamination [33][34][35], b) it makes it easy to separate cell mass for the bulk liquid [36][37][38][39][40][41][42][43], c) it reduces production costs [18,36,42], d) biocatalyst can be recycled [43], e) fermentation time can be reduced [7,18], f) cells can be protected from inhibitors [44] g) more ethanol production compared to free cells [7,18,38,35]…”