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Waste Apple Pomace Conversion to Acrylic Acid: Economic and Potential Environmental Impact Assessments. FERMENTATION 2022. [DOI: 10.3390/fermentation8010021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The global demand for acrylic acid (AA) is increasing due to its wide range of applications. Due to this growing demand, alternative AA production strategies must be explored to avoid the exacerbation of prevailing climate and global warming issues since current AA production strategies involve fossil resources. Investigations regarding alternative strategies for AA production therefore constitute an important research interest. The present study assesses waste apple pomace (WAP) as a feedstock for sustainable AA production. To undertake this assessment, process models based on two production pathways were designed, modelled and simulated in ASPEN plus® software. The two competing production pathways investigated included a process incorporating WAP conversion to lactic acid (LA) prior to LA dehydration to generate AA (denoted as the fermentation–dehydration, i.e., FD, pathway) and another process involving WAP conversion to propylene prior to propylene oxidation to generate AA (denoted as the thermochemical–fermentation–oxidation, i.e., TFO, pathway). Economic performance and potential environmental impact of the FD and TFO pathways were assessed using the metrics of minimum selling price (MSP) and potential environmental impacts per h (PEI/h). The study showed that the FD pathway presented an improved economic performance (MSP of AA: USD 1.17 per kg) compared to the economic performance (MSP of AA: USD 1.56 per kg) of the TFO pathway. Crucially, the TFO process was determined to present an improved environmental performance (2.07 kPEI/h) compared to the environmental performance of the FD process (8.72 kPEI/h). These observations suggested that the selection of the preferred AA production pathway or process will require a tradeoff between economic and environmental performance measures via the integration of a multicriteria decision assessment in future work.
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Schwarz D, Schoenenwald AKJ, Dörrstein J, Sterba J, Kahoun D, Fojtíková P, Vilímek J, Schieder D, Zollfrank C, Sieber V. Biosynthesis of poly-3-hydroxybutyrate from grass silage by a two-stage fermentation process based on an integrated biorefinery concept. BIORESOURCE TECHNOLOGY 2018; 269:237-245. [PMID: 30179757 DOI: 10.1016/j.biortech.2018.08.064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/14/2018] [Accepted: 08/16/2018] [Indexed: 06/08/2023]
Abstract
Grass silage as a renewable feedstock for an integrated biorefinery includes nutrients and carbon sources directly available in the press juice (PJ) and in lignocellulosic saccharides from the plant framework. Here, a novel two-stage fed-batch fermentation process for biosynthesis of poly-3-hydroxybutyrate (PHB) by Cupriavidus necator DSM 531 is presented. For bacterial growth, nutrient-rich PJ was employed as a fermentation medium, without any supplements. Saccharides derived from the mechano-enzymatic hydrolysis of the press cake (PC) were subjected to a lactic acid fermentation process, before the fermentation products were fed into the polymer accumulation phase. By combination of pH-stat feeding and cell recycling, the PHB content in 22 g L-1 total-dry cells reached 39% after 32 h of cultivation. Using mimicked hydrolyzate of diluted PJ artificially supplemented with glucose and xylose, the resulting cell dry weight of 21 g L-1 contained 42% PHB.
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Affiliation(s)
- Dominik Schwarz
- Technical University of Munich, Chair of Chemistry of Biogenic Resources, Schulgasse 16, 94315 Straubing, Germany
| | - Amelie K J Schoenenwald
- Technical University of Munich, Chair of Chemistry of Biogenic Resources, Schulgasse 16, 94315 Straubing, Germany
| | - Jörg Dörrstein
- Technical University of Munich, Biogenic Polymers, Schulgasse 16, 94315 Straubing, Germany
| | - Jan Sterba
- Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - David Kahoun
- Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Pavla Fojtíková
- Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Josef Vilímek
- Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Doris Schieder
- Technical University of Munich, Chair of Chemistry of Biogenic Resources, Schulgasse 16, 94315 Straubing, Germany.
| | - Cordt Zollfrank
- Technical University of Munich, Biogenic Polymers, Schulgasse 16, 94315 Straubing, Germany
| | - Volker Sieber
- Technical University of Munich, Chair of Chemistry of Biogenic Resources, Schulgasse 16, 94315 Straubing, Germany
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Hudeckova H, Neureiter M, Obruca S, Frühauf S, Marova I. Biotechnological conversion of spent coffee grounds into lactic acid. Lett Appl Microbiol 2018; 66:306-312. [PMID: 29330879 DOI: 10.1111/lam.12849] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 12/25/2017] [Accepted: 01/06/2018] [Indexed: 11/28/2022]
Abstract
This work investigates the potential bioconversion of spent coffee grounds (SCG) into lactic acid (LA). SCG were hydrolysed by a combination of dilute acid treatment and subsequent application of cellulase. The SCG hydrolysate contained a considerable amount of reducing sugars (9·02 ± 0·03 g l-1 , glucose; 26·49 ± 0·10 g l-1 galactose and 2·81 ± 0·07 g l-1 arabinose) and it was used as a substrate for culturing several lactic acid bacteria (LAB) and LA-producing Bacillus coagulans. Among the screened micro-organisms, Lactobacillus rhamnosus CCM 1825 was identified as the most promising producer of LA on a SCG hydrolysate. Despite the inhibitory effect exerted by furfural and phenolic compounds in the medium, reasonably high LA concentrations (25·69 ± 1·45 g l-1 ) and yields (98%) were gained. Therefore, it could be demonstrated that SCG is a promising raw material for the production of LA and could serve as a feedstock for the sustainable large-scale production of LA. SIGNIFICANCE AND IMPACT OF THE STUDY Spent coffee grounds (SCG) represent solid waste generated in millions of tonnes by coffee-processing industries. Their disposal represents a serious environmental problem; however, SCG could be valorized within a biorefinery concept yielding various valuable products. Herein, we suggest that SCG can be used as a complex carbon source for the lactic acid production.
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Affiliation(s)
- H Hudeckova
- Institute of Food Science and Biotechnology, Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic.,Materials Research Centre, Brno University of Technology, Brno, Czech Republic
| | - M Neureiter
- Department of Agrobiotechnology, University of Natural Resources and Life Sciences, Vienna, Tulln, Austria
| | - S Obruca
- Institute of Food Science and Biotechnology, Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic.,Materials Research Centre, Brno University of Technology, Brno, Czech Republic
| | - S Frühauf
- Department of Agrobiotechnology, University of Natural Resources and Life Sciences, Vienna, Tulln, Austria
| | - I Marova
- Institute of Food Science and Biotechnology, Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic.,Materials Research Centre, Brno University of Technology, Brno, Czech Republic
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Montipó S, Ballesteros I, Fontana RC, Liu S, Martins AF, Ballesteros M, Camassola M. Integrated production of second generation ethanol and lactic acid from steam-exploded elephant grass. BIORESOURCE TECHNOLOGY 2018; 249:1017-1024. [PMID: 30045483 DOI: 10.1016/j.biortech.2017.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 10/31/2017] [Accepted: 11/01/2017] [Indexed: 06/08/2023]
Abstract
Elephant grass was subjected to steam explosion to enhance cellulose accessibility and convert it into ethanol. After catalyzed pretreatment at 190 °C for 5 min, enzymatic hydrolysis was carried out using high rate of solid loading combined with different enzyme dosages. Assays employing 20% (w/v) solids loading and an enzyme dosage of 20 FPU g-1 substrate led to a yield of 86.02 g glucose released per 100 g potential glucose in the water insoluble solids. This condition was selected to carry out the simultaneous saccharification and fermentation procedure through S. cerevisiae CAT-1, producing 42.25 g L-1 ethanol with a yield of 74.57% regard to the maximum theoretical. The liquor containing C5 and C6-sugars was successfully converted into lactic acid using L. buchneri NRRL B-30929, resulting in 13.35 g L-1 with a yield of 68.21% in relation to the maximum theoretical.
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Affiliation(s)
- Sheila Montipó
- Biotechnology Institute, University of Caxias do Sul, Caxias do Sul, RS 95070-560, Brazil.
| | - Ignacio Ballesteros
- Renewable Energies Department, CIEMAT - Research Centre for Energy, Environment and Technology, Madrid 28040, Spain
| | | | - Siqing Liu
- Renewable Product Technology, NCAUR-ARS, U.S. Department of Agriculture, Peoria, IL 61604, USA
| | | | - Mercedes Ballesteros
- Renewable Energies Department, CIEMAT - Research Centre for Energy, Environment and Technology, Madrid 28040, Spain
| | - Marli Camassola
- Biotechnology Institute, University of Caxias do Sul, Caxias do Sul, RS 95070-560, Brazil.
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Pleissner D, Qi Q, Gao C, Rivero CP, Webb C, Lin CSK, Venus J. Valorization of organic residues for the production of added value chemicals: A contribution to the bio-based economy. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2015.12.016] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Guo W, He R, Ma L, Jia W, Li D, Chen S. Construction of a constitutively expressed homo-fermentative pathway in Lactobacillus brevis. Appl Microbiol Biotechnol 2014; 98:6641-50. [DOI: 10.1007/s00253-014-5703-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 03/10/2014] [Accepted: 03/17/2014] [Indexed: 10/25/2022]
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Sakdaronnarong C, Srimarut N, Lucknakhul N, Na-songkla N, Jonglertjunya W. Two-step acid and alkaline ethanolysis/alkaline peroxide fractionation of sugarcane bagasse and rice straw for production of polylactic acid precursor. Biochem Eng J 2014. [DOI: 10.1016/j.bej.2014.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Zhang L, You T, Zhang L, Li M, Xu F. Comprehensive utilization of waste hemicelluloses during ethanol production to increase lactic acid yield: from pretreatment to fermentation. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:494. [PMID: 25606053 PMCID: PMC4300168 DOI: 10.1186/s13068-014-0189-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 12/16/2014] [Indexed: 05/23/2023]
Abstract
BACKGROUND Reducing the cost of producing cellulosic ethanol is essential for the industrialization of biorefinery. Several processes are currently under investigation, but few of these techniques are entirely satisfactory in terms of competitive cost or environmental impact. In this study, a new ethanol and lactic acid (LA) coproduction is proposed. The technique involved addition of waste alkaline peroxide pretreated hydrolysate (mainly LA and hemicelluloses) to the reaction mixture after ethanol fermentation (mainly LA and xylose) to reduce the ethanol production cost. RESULTS The following processes were investigated to optimize LA production: no addition of hemicelluloses or hydrolysate, addition of recycled hemicelluloses, and addition of concentrated hydrolysate. The addition of concentrated hydrolysate at 48 hours, which resulted in a maximum LA concentration of 22.3 g/L, was the most environment-friendly and cost-effective process. After the improved fermentation, 361 mg LA and 132 mg ethanol were produced from 1 g of raw poplar wood. That is, the production of one gallon of ethanol produced $9 worth of LA. CONCLUSIONS The amount of LA produced from the pretreated hydrolysate and reaction mixture after ethanol fermentation cannot be underestimated. The recovery of hydrolysate rich in LA and hemicelluloses (or xylose) significantly improved LA yield and further reduced the ethanol production cost.
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Affiliation(s)
- Liming Zhang
- />Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
| | - Tingting You
- />Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
| | - Lu Zhang
- />Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
| | - Mingfei Li
- />Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
- />MOE Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Beijing, 100083 China
| | - Feng Xu
- />Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
- />MOE Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Beijing, 100083 China
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Waste valorization by biotechnological conversion into added value products. Appl Microbiol Biotechnol 2013; 97:6129-47. [DOI: 10.1007/s00253-013-5014-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/20/2013] [Accepted: 05/21/2013] [Indexed: 11/25/2022]
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Castillo Martinez FA, Balciunas EM, Salgado JM, Domínguez González JM, Converti A, Oliveira RPDS. Lactic acid properties, applications and production: A review. Trends Food Sci Technol 2013. [DOI: 10.1016/j.tifs.2012.11.007] [Citation(s) in RCA: 401] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ye L, Zhou X, Hudari MSB, Li Z, Wu JC. Highly efficient production of L-lactic acid from xylose by newly isolated Bacillus coagulans C106. BIORESOURCE TECHNOLOGY 2013; 132:38-44. [PMID: 23399496 DOI: 10.1016/j.biortech.2013.01.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 12/30/2012] [Accepted: 01/04/2013] [Indexed: 06/01/2023]
Abstract
Cost-effective production of optically pure lactic acid from lignocellulose sugars is commercially attractive but challenging. Bacillus coagulans C106 was isolated from environment and used to produce l-lactic acid from xylose at 50°C and pH 6.0 in mineral salts medium containing 1-2% (w/v) of yeast extract without sterilizing the medium before fermentation. In batch fermentation with 85g/L of xylose, lactic acid titer and productivity reached 83.6g/L and 7.5g/Lh, respectively. When fed-batch (120+80+60g/L) fermentation was applied, they reached 215.7g/L and 4.0g/Lh, respectively. In both cases, the lactic acid yield and optical purity reached 95% and 99.6%, respectively. The lactic acid titer and productivity on xylose are the highest among those ever reported. Ca(OH)2 was found to be a better neutralizing agent than NaOH in terms of its giving higher lactic acid titer (1.2-fold) and productivity (1.8-fold) under the same conditions.
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Affiliation(s)
- Lidan Ye
- Institute of Chemical and Engineering Sciences, Agency for Sciences, Technology and Research, 1 Pesek Road, Jurong Island, Singapore 627833, Singapore
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Abdel-Rahman MA, Tashiro Y, Sonomoto K. Lactic acid production from lignocellulose-derived sugars using lactic acid bacteria: overview and limits. J Biotechnol 2011; 156:286-301. [PMID: 21729724 DOI: 10.1016/j.jbiotec.2011.06.017] [Citation(s) in RCA: 264] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 05/31/2011] [Accepted: 06/17/2011] [Indexed: 10/18/2022]
Abstract
Lactic acid is an industrially important product with a large and rapidly expanding market due to its attractive and valuable multi-function properties. The economics of lactic acid production by fermentation is dependent on many factors, of which the cost of the raw materials is very significant. It is very expensive when sugars, e.g., glucose, sucrose, starch, etc., are used as the feedstock for lactic acid production. Therefore, lignocellulosic biomass is a promising feedstock for lactic acid production considering its great availability, sustainability, and low cost compared to refined sugars. Despite these advantages, the commercial use of lignocellulose for lactic acid production is still problematic. This review describes the "conventional" processes for producing lactic acid from lignocellulosic materials with lactic acid bacteria. These processes include: pretreatment of the biomass, enzyme hydrolysis to obtain fermentable sugars, fermentation technologies, and separation and purification of lactic acid. In addition, the difficulties associated with using this biomass for lactic acid production are especially introduced and several key properties that should be targeted for low-cost and advanced fermentation processes are pointed out. We also discuss the metabolism of lignocellulose-derived sugars by lactic acid bacteria.
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Affiliation(s)
- Mohamed Ali Abdel-Rahman
- Laboratory of Microbial Technology, Division of Applied Molecular Microbiology and Biomass Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan
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l(+)-Lactic acid production from non-food carbohydrates by thermotolerant Bacillus coagulans. J Ind Microbiol Biotechnol 2010; 38:599-605. [DOI: 10.1007/s10295-010-0796-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 07/22/2010] [Indexed: 10/19/2022]
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Walton SL, Bischoff KM, van Heiningen ARP, van Walsum GP. Production of lactic acid from hemicellulose extracts by Bacillus coagulans MXL-9. J Ind Microbiol Biotechnol 2010; 37:823-30. [DOI: 10.1007/s10295-010-0727-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 04/16/2010] [Indexed: 10/19/2022]
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Capillary electrophoresis for the monitoring of carboxylic acid production by Gluconobacter oxydans. J Chromatogr A 2010; 1217:1537-42. [DOI: 10.1016/j.chroma.2009.12.075] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Revised: 12/22/2009] [Accepted: 12/24/2009] [Indexed: 11/17/2022]
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Performances of Lactobacillus brevis for producing lactic acid from hydrolysate of lignocellulosics. Appl Biochem Biotechnol 2009; 161:124-36. [PMID: 19937398 DOI: 10.1007/s12010-009-8857-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 11/05/2009] [Indexed: 10/20/2022]
Abstract
Utilizing all forms of sugars derived from lignocellulosic biomass via various pretreatment and hydrolysis process is a primary criterion for selecting a microorganism to produce biofuels and biochemicals. A broad carbon spectra and potential inhibitors such as furan, phenol compounds and weak acids are two major obstacles that limited the application of dilute-acid hydrolysate of lignocellulosics in lactic acid fermentation. Two strains of bacteria isolated from sour cabbage, S3F4 (Lactobacillus brevis) and XS1T3-4 (Lactobacillus plantrum), exhibited the ability to utilize various sugars present in dilute-acid hydrolysate of biomass. The S3F4 strain also showed strong resistance to potential fermentation inhibitors such as ferulic acid and furfural. Fermentation in flasks by this strain resulted in 39.1 g/l of lactic acid from dilute acid hydrolysates of corncobs that had initial total sugar concentration of 56.9 g/l (xylose, 46.4 g/l; glucose, 4.0 g/l; arabinose, 6.5 g/l). The hydrolysate of corncobs was readily utilized by S3F4 without detoxification, and the lactic acid concentration obtained in this study was higher compared to other reports.
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Doran-Peterson J, Cook DM, Brandon SK. Microbial conversion of sugars from plant biomass to lactic acid or ethanol. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 54:582-592. [PMID: 18476865 DOI: 10.1111/j.1365-313x.2008.03480.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Concerns for our environment and unease with our dependence on foreign oil have renewed interest in converting plant biomass into fuels and 'green' chemicals. The volume of plant matter available makes lignocellulose conversion desirable, although no single isolated organism has been shown to depolymerize lignocellulose and efficiently metabolize the resulting sugars into a specific product. This work reviews selected chemicals and fuels that can be produced from microbial fermentation of plant-derived cell-wall sugars and directed engineering for improvement of microbial biocatalysts. Lactic acid and ethanol production are highlighted, with a focus on engineered Escherichia coli.
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Affiliation(s)
- Joy Doran-Peterson
- Microbiology Department, 1000 Cedar Street, 527 Biological Sciences Building, University of Georgia, Athens, GA 30602, USA.
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Liu S, Skinner-Nemec KA, Leathers TD. Lactobacillus buchneri strain NRRL B-30929 converts a concentrated mixture of xylose and glucose into ethanol and other products. J Ind Microbiol Biotechnol 2007; 35:75-81. [PMID: 17940817 DOI: 10.1007/s10295-007-0267-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Accepted: 09/25/2007] [Indexed: 11/25/2022]
Abstract
Lactobacillus buchneri strain NRRL B-30929 was isolated from a fuel ethanol production facility. This heterofermentative, facultative anaerobe can utilize xylose as a sole carbon source and tolerates up to 12% ethanol. Carbohydrate utilization (API, Biomerieux) and Phenotype Microarrays (PM, Biolog) analyses indicated that the strain is able to metabolize a broad spectrum of carbon sources including various monosaccharides (C5 and C6), disaccharides and oligosaccharides, with better rates under anaerobic conditions. In pH-controlled bioreactors, the bacterium consumed xylose and glucose simultaneously at high concentrations (125 g L(-1), pH 6.0). The major fermentation products were lactate (52 g L(-1)), acetate (26 g L(-1)) and ethanol (12 g L(-1)). The strain ferments glucose alone (pH 4.0) into lactate and ethanol with a molar ratio of 1.03:1. This strain will be further explored via genetic engineering for potential applications in biomass conversion.
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Affiliation(s)
- Siqing Liu
- Bioproducts and Biocatalysis Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, 1815 N. University St, Peoria, IL 61604, USA.
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Abstract
Owing to technical improvements in the processes used to produce ethanol from biomass, construction of at least two waste-to-ethanol production plants in the United States is expected to start this year. Although there are a number of robust fermentation microorganisms available, initial pretreatment of the biomass and costly cellulase enzymes remain critical targets for process and cost improvements. A highly efficient, very low-acid pretreatment process is approaching pilot testing, while research on cellulases for ethanol production is expanding at both enzyme and organism level.
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Affiliation(s)
- J R Mielenz
- White Cliff Biosystems Co, 107 Lake Meadow Drive, Johnson City, Tennessee 37615, USA.
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