Development of a low-cost fermentation medium for ethanol production from biomass

Kadam, Kiran L.; Newman, Mildred M.

doi:10.1007/s002530050985

Cited by 90 publications

(44 citation statements)

References 4 publications

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“…Hence, extra costs due to external nutrient supplement are deemed unavoidable (Kadam and Newman, 1997). Unlike most cellulosics, corn distiller's dried grains with solubles (DDGS) is a nutrient-rich feedstock derived from the corn-based ethanol industry (Spiehs et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Ethanolic fermentation of hydrolysates from ammonia fiber expansion (AFEX) treated corn stover and distillers grain without detoxification and external nutrient supplementation

Lau

Dale

Balan

2007

Biotech & Bioengineering

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External nutrient supplementation and detoxification of hydrolysate significantly increase the production cost of cellulosic ethanol. In this study, we investigated the feasibility of fermenting cellulosic hydrolysates without washing, detoxification or external nutrient supplementation using ethanologens Escherichia coli KO11 and the adapted strain ML01 at low initial cell density (16 mg dry weight/L). The cellulosic hydrolysates were derived from enzymatically digested ammonia fiber expansion (AFEX)-treated corn stover and dry distiller's grain and solubles (DDGS) at high solids loading (18% by weight). The adaptation was achieved through selective evolution of KO11 on hydrolysate from AFEX-treated corn stover. All cellulosic hydrolysates tested (36-52 g/L glucose) were fermentable. Regardless of strains, metabolic ethanol yields were near the theoretical limit (0.51 g ethanol/g consumed sugar). Volumetric ethanol productivity of 1.2 g/h/L was achieved in fermentation on DDGS hydrolysate and DDGS improved the fermentability of hydrolysate from corn stover. However, enzymatic hydrolysis and xylose utilization during fermentation were the bottlenecks for ethanol production from corn stover at these experimental conditions. In conclusion, fermentation under the baseline conditions was feasible. Utilization of nutrient-rich feedstocks such as DDGS in fermentation can replace expensive media supplementation.

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Section: Introductionmentioning

confidence: 99%

Ethanolic fermentation of hydrolysates from ammonia fiber expansion (AFEX) treated corn stover and distillers grain without detoxification and external nutrient supplementation

Lau

Dale

Balan

2007

Biotech & Bioengineering

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“…The ability to generate and convert fermentable sugars from lignocellulosic materials to ethanol in a cost-effective fashion is the central technological challenge to fully unlock its commercial potential (3). Unfortunately, fermentation of hydrolysates derived from pretreated lignocellulosic biomass is often preceded by washing (4), nutrient supplementation (5,6), and detoxification (7,8), which are very costly processes (9,10). The fermentability of a hydrolysate is strongly dependent on the feedstock pretreatment and strain selection.…”

mentioning

confidence: 99%

Cellulosic ethanol production from AFEX-treated corn stover using Saccharomyces cerevisiae 424A(LNH-ST)

Lau

Dale²

2009

Proc. Natl. Acad. Sci. U.S.A.

329

200

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Current technology using corn stover (CS) as feedstock, Ammonia Fiber Expansion (AFEX) as the pretreatment technology, and Saccharomyces cerevisiae 424A(LNH-ST) as the ethanologenic strain in Separate Hydrolysis and Fermentation was able to achieve 191.5 g EtOH/kg untreated CS, at an ethanol concentration of 40.0 g/L (5.1 vol/vol%) without washing of pretreated biomass, detoxification, or nutrient supplementation. Enzymatic hydrolysis at high solids loading was identified as the primary bottleneck affecting overall ethanol yield and titer. Degradation compounds in AFEX-pretreated biomass were shown to increase metabolic yield and specific ethanol production while decreasing the cell biomass generation. Nutrients inherently present in CS and those resulting from biomass processing are sufficient to support microbial growth during fermentation. This platform offers the potential to improve the economics of cellulosic ethanol production by reducing the costs associated with raw materials, process water, and capital equipment.AFEX ͉ fermentation ͉ Lignocellulose ͉ biofuel

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“…It was also previously reported that the addition of activated carbon is effective in promoting C. krusei IA-1 growth in repeated cultivations using spent media, 18 and that it is possible to reuse spent media by adding activated carbon, 19 with the aim of reducing the cost of raw materials. 20,21 Therefore, coupling fermentation processes employing C. krusei IA-1 in the presence of activated carbon with pervaporation using silicone rubber-coated silicalite membranes would cost-effectively provide reliably refined bioethanol.…”

Section: Resultsmentioning

confidence: 99%

“…To lessen the deterioration in pervaporation performance during bioethanol separation, CSL and peptone concentrations in fermentation broths should be maintained at low values (reducing the associated cost of the medium) but at concentrations that can give a high ethanol production rate. 20 Figure 4 shows the effects of succinate addition on pervaporation performance. The decreased performance is clearly different from those observed following the addition of nutrients such as peptone, yeast extract, and CSL.…”

Section: Effects Of Components In Fermentation Broths On Pervaporatiomentioning

confidence: 99%

Processing of ethanol fermentation broths by Candida krusei to separate bioethanol by pervaporation using silicone rubber‐coated silicalite membranes

Ikegami

Morita

Nakayama

et al. 2009

J of Chemical Tech & Biotech

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BACKGROUND: Pervaporation employing ethanol-permselective silicalite membranes as an alternative to distillation is a promising approach for refining low-concentration bioethanol solutions. However, to make the separation process practicable, it is extremely important to avoid the problems caused by the adsorption of succinate on the membrane during the separation process. In this work, the pervaporation of an ethanol fermentation broth without succinate was investigated, as well as the influence of several fermentation broth nutrient components.

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Development of a low-cost fermentation medium for ethanol production from biomass

Cited by 90 publications

References 4 publications

Ethanolic fermentation of hydrolysates from ammonia fiber expansion (AFEX) treated corn stover and distillers grain without detoxification and external nutrient supplementation

Ethanolic fermentation of hydrolysates from ammonia fiber expansion (AFEX) treated corn stover and distillers grain without detoxification and external nutrient supplementation

Cellulosic ethanol production from AFEX-treated corn stover using Saccharomyces cerevisiae 424A(LNH-ST)

Processing of ethanol fermentation broths by Candida krusei to separate bioethanol by pervaporation using silicone rubber‐coated silicalite membranes

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