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1.
Bioresour Technol ; 208: 42-48, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26918837

RESUMO

A techno-economic analysis was conducted for a simplified lignocellulosic ethanol production process developed and proven by the University of Florida at laboratory, pilot, and demonstration scales. Data obtained from all three scales of development were used with Aspen Plus to create models for an experimentally-proven base-case and 5 hypothetical scenarios. The model input parameters that differed among the hypothetical scenarios were fermentation time, enzyme loading, enzymatic conversion, solids loading, and overall process yield. The minimum ethanol selling price (MESP) varied between 50.38 and 62.72 US cents/L. The feedstock and the capital cost were the main contributors to the production cost, comprising between 23-28% and 40-49% of the MESP, respectively. A sensitivity analysis showed that overall ethanol yield had the greatest effect on the MESP. These findings suggest that future efforts to increase the economic feasibility of a cellulosic ethanol process should focus on optimization for highest ethanol yield.


Assuntos
Biotecnologia/economia , Etanol/economia , Etanol/metabolismo , Modelos Econômicos , Saccharum/química , Biotecnologia/métodos , Celulose/química , Fermentação , Investimentos em Saúde , Modelos Teóricos , Ácidos Fosfóricos/química
2.
Bioresour Technol ; 198: 533-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26432057

RESUMO

In this study, a moderate thermophile Clostridium thermobutyricum is shown to ferment the sugars in sweet sorghum juice treated with invertase and supplemented with tryptone (10 g L(-1)) and yeast extract (10 g L(-1)) at 50°C to 44 g L(-1) butyrate at a calculated highest volumetric productivity of 1.45 g L(-1)h(-1) (molar butyrate yield of 0.85 based on sugars fermented). This volumetric productivity is among the highest reported for batch fermentations. Sugars from acid and enzyme-treated sweet sorghum bagasse were also fermented to butyrate by this organism with a molar yield of 0.81 (based on the amount of cellulose and hemicellulose). By combining the results from juice and bagasse, the calculated yield of butyric acid is approximately 90 kg per tonne of fresh sweet sorghum stalk. This study demonstrates that C. thermobutyricum can be an effective microbial biocatalyst for production of bio-based butyrate from renewable feedstocks at 50°C.


Assuntos
Biotecnologia/métodos , Ácido Butírico/metabolismo , Clostridium/metabolismo , Sorghum/metabolismo , Metabolismo dos Carboidratos , Celulose/química , Celulose/metabolismo , Fermentação , Peptonas/química , Polissacarídeos/metabolismo , Sorghum/química , beta-Frutofuranosidase/metabolismo
3.
Curr Opin Biotechnol ; 22(3): 312-9, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21600756

RESUMO

Barriers to the commercialization of lignocellulosic ethanol include the development of more robust biocatalysts, reduction of cellulase costs, and high capital cost associated with a complex process. Improvements have been made in all areas during the past two years. Oxidoreductases, transporters, and regulators have been identified that can increase the tolerance of biocatalysts to inhibitors formed during pretreatment. Biocatalysts are being developed that grow under conditions that are optimal for cellulase activity and others have been engineered to produce glycoside hydrolases. Ethanol yields resulting from most current process configurations are similar, approximately 0.21 g ethanol/g dry cellulosic feedstock. Potentially, this can be increased to at least 0.27 g ethanol/g biomass (83 gal/ton) using simpler processes.


Assuntos
Etanol/economia , Fermentação , Biomassa , Celulase/metabolismo , Celulose/metabolismo , Indústria Química/métodos , Economia , Etanol/metabolismo
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