Production of fuel ethanol from rye and triticale by very-high-gravity (VHG) fermentation

Wang, S.; Thomas, K. C.; Ingledew, W. M.; Sosulski, K.; Sosulski, F. W.

doi:10.1007/bf02788811

Cited by 30 publications

(20 citation statements)

References 17 publications

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“…RQ-controlled fermentation led to a lower maximum specific ethanol production rate and average ethanol productivity; however, it was possible to reach high ethanol production (85 g · liter Ϫ1 in 30 h). The obtained mass ratio of ethanol production to glycerol production of 50 was the highest among the highly productive ethanol production processes reported in the literature (within 10 to 20) (33,39). Previous attempts at reducing the glycerol formation by construction of mutant strains were reported in the literature (18,19).…”

Section: Discussionmentioning

confidence: 83%

Minimization of Glycerol Production during the High-Performance Fed-Batch Ethanolic Fermentation Process in Saccharomyces cerevisiae , Using a Metabolic Model as a Prediction Tool

Bideaux

Alfenore

Cameleyre

et al. 2006

Appl Environ Microbiol

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On the basis of knowledge of the biological role of glycerol in the redox balance of Saccharomyces cerevisiae, a fermentation strategy was defined to reduce the surplus formation of NADH, responsible for glycerol synthesis. A metabolic model was used to predict the operating conditions that would reduce glycerol production during ethanol fermentation. Experimental validation of the simulation results was done by monitoring the inlet substrate feeding during fed-batch S. cerevisiae cultivation in order to maintain the respiratory quotient (RQ) (defined as the CO 2 production to O 2 consumption ratio) value between 4 and 5. Compared to previous fermentations without glucose monitoring, the final glycerol concentration was successfully decreased. Although RQ-controlled fermentation led to a lower maximum specific ethanol production rate, it was possible to reach a high level of ethanol production: 85 g · liter ؊1 with 1.7 g · liter ؊1 glycerol in 30 h. We showed here that by using a metabolic model as a tool in prediction, it was possible to reduce glycerol production in a very high-performance ethanolic fermentation process.It is well-known that glycerol is a major by-product during alcoholic fermentation in the yeast Saccharomyces cerevisiae. The role of glycerol in the cellular redox balance (5) and in osmoregulation (4, 16) have been reported in the literature. Participating in the cell redox balance, glycerol is produced by Saccharomyces cerevisiae to reoxidize surplus NADH, formed in the synthesis of biomass and secondary fermentation products, to NAD ϩ (5). Two different strategies for modulating the production of glycerol have been reported in the literature. One strategy is to change the operating conditions of the fermentation process (i.e., aeration levels, stress conditions [salts, acids, osmotic stress, heat shock . . .]) (3,4,8,11,12,19,31,40,42); another is to use genetically modified strains. Engineered strains were constructed by overexpressing and repressing components of the glycerol synthesis pathway (14,18,19,21,25).Complementing biochemical and metabolic engineering experimental approaches, mathematical models may also be useful for interpretation and prediction of biochemical processes. Process models consist in coupling mass balance equations at the reactor scale and at the cellular scale (29). Cells can be modeled at different levels: unstructured models on the population level (15, 27) or structured models on the cellular level. The latter can be a compartmental model (41) or a metabolic regulator model (28). Constraints on carbon, energy, and redox potential linked to the metabolic network can be taken into account by a metabolic model that contains a complete set of metabolic pathways involved in biomass synthesis, energy production, substrate degradation, and cometabolite production (30,35).Metabolic flux analysis is generally used to quantify intracellular fluxes in the central metabolism of microorganisms (7,9,11,22,24,43), but it has had a limited impact due to the lack of regulatory...

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Section: Discussionmentioning

confidence: 83%

Minimization of Glycerol Production during the High-Performance Fed-Batch Ethanolic Fermentation Process in Saccharomyces cerevisiae , Using a Metabolic Model as a Prediction Tool

Bideaux

Alfenore

Cameleyre

et al. 2006

Appl Environ Microbiol

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“…Although the biological process of ethanol production is similar in all distilleries, the main raw materials used in ethanol plants in different countries may differ entirely. Different raw materials may raise specific problems during the production of ethanol, such as excessive foaming or high viscosity of mashes made from oats, barley and rye . Research in this area, in particular, may aid ethanol producers in rural areas in selecting the most economical raw materials.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous saccharification and fermentation of native rye, wheat and triticale starch

et al. 2019

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BACKGROUND The increasing global demand for starchy raw material requires new methods for obtaining ethanol from a range of plants using environmentally friendly methods. Granular starch‐hydrolyzing enzymes (GSHE) can effectively support the development of the distillery industry. RESULTS The aim of this study was to evaluate the effectiveness of simultaneous saccharification and fermentation of native rye, wheat or triticale starch. Mashes were prepared using methods that limit water and energy consumption (pre‐hydrolysis at 35 °C for 30 min). The results show that the degree of starch saccharification depended on the raw material. However, the highest yields of ethanol were obtained with 100 kg of triticale mashes (38.9 ± 1.4 L absolute alcohol) as compared to rye and wheat mashes. The concentration of dry matter (between 250 and 280 g L−1) in the mashes was not associated with a decrease in ethanol yield and improved efficiency in the case of wheat and triticale. CONCLUSION Simultaneous saccharification and fermentation offers a low‐cost and environmentally friendly alternative to existing procedures for industrial ethanol production, which may be of particular interest to raw‐spirit producers, as well as to the food and fermentation industry at large. © 2019 Society of Chemical Industry

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“…Triticale is reported to have equal value to wheat grain for ethanol production (Wang et al, 1997(Wang et al, , 1998. It is purported to have an advantage over wheat in terms of net environmental benefit, owing to its com-paratively higher yields (Salmon, 2004) and lower crop input requirements (Davis-Knight and Weightman, 2008).…”

Section: Introductionmentioning

confidence: 97%

Nutritive value of single-screw extruded and nonextruded triticale distillers dried grains with solubles, with and without an enzyme complex, for broilers

2010

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The nutritive value of triticale distillers dried grains with solubles (DDGS) for broilers was investigated in 2 experiments. In experiment 1, four hundred male broilers housed in battery cages were fed diets including 15 or 30% triticale DDGS (extruded or not) or a basal diet, supplemented with or without a multi-enzyme complex from d 21 to 28. Birds were killed and ileal digesta was collected on d 28 to establish the apparent ileal nutrient digestibility (AID) coefficients for both assay diets and DDGS as test ingredients based on 5 cages per diet. In experiment 2, a 42-d performance study compared growth phase-specific diets formulated to similar levels of AME, CP, and digestible lysine with graded levels (0, 5, or 10%) of triticale DDGS inclusion based on a minimum of 4 pens per diet x sex combination. Breast muscle weight and percentage yield were determined on d 37 by sampling 5 birds per pen. In experiment 1, there was a significant (P < 0.05) DDGS level of inclusion x enzyme interaction for CP, lysine, methionine, tryptophan, isoleucine, histidine, and phenylalanine, such that the AID increased with enzyme supplementation based on 15% but not 30% DDGS inclusion. At 15% DDGS inclusion, enzyme supplementation increased the AID of these nutrients in DDGS between 6 and 19 percentage units. Extrusion of triticale DDGS increased (P < 0.05) the AID of GE, CP, methionine, tryptophan, branched-chain amino acids, and phenylalanine between 3 and 8 percentage units. In experiment 2, feeding up to 10% triticale DDGS had no adverse effect on feed intake, weight gain, or feed efficiency of broilers compared with controls over the 42-d study. Feeding up to 10% triticale DDGS did not affect breast weight or yield on d 37. In conclusion, feed enzyme complex supplementation and extrusion both increased the nutritive value of triticale DDGS for broilers. Triticale DDGS can be fed at up to 10% of practical broiler diets without adverse effect on performance and breast muscle yield.

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Production of fuel ethanol from rye and triticale by very-high-gravity (VHG) fermentation

Cited by 30 publications

References 17 publications

Minimization of Glycerol Production during the High-Performance Fed-Batch Ethanolic Fermentation Process in Saccharomyces cerevisiae , Using a Metabolic Model as a Prediction Tool

Minimization of Glycerol Production during the High-Performance Fed-Batch Ethanolic Fermentation Process in Saccharomyces cerevisiae , Using a Metabolic Model as a Prediction Tool

Simultaneous saccharification and fermentation of native rye, wheat and triticale starch

Nutritive value of single-screw extruded and nonextruded triticale distillers dried grains with solubles, with and without an enzyme complex, for broilers

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