排序方式: 共有120条查询结果,搜索用时 15 毫秒
101.
Hui Li Nag-Jong Kim Min Jiang Jong Won Kang Ho Nam Chang 《Bioresource technology》2009,100(13):3245-3251
Bermudagrass, reed and rapeseed were pretreated with phosphoric acid–acetone and used for ethanol production by means of simultaneous saccharification and fermentation (SSF) with a batch and fed-batch mode. When the batch SSF experiments were conducted in a 3% low effective cellulose, about 16 g/L of ethanol were obtained after 96 h of fermentation. When batch SSF experiments were conducted with a higher cellulose content (10% effective cellulose for reed and bermudagrass and 5% for rapeseed), higher ethanol concentrations and yields (of more than 93%) were obtained. The fed-batch SSF strategy was adopted to increase the ethanol concentration further. When a higher water-insoluble solid (up to 36%) was applied, the ethanol concentration reached 56 g/L of an inhibitory concentration of the yeast strain used in this study at 38 °C. The results show that the pretreated materials can be used as good feedstocks for bioethanol production, and that the phosphoric acid–acetone pretreatment can effectively yield a higher ethanol concentration. 相似文献
102.
Microalgae are diverse microorganisms inhabiting a wide range of habitats with only a small fraction being cultivated for human use. Recently, interest in microalgal research has increased in the quest for alternative renewable fuels due to possible depletion of fossil fuels in the near future. However, costly downstream processing has hampered the commercialization of biofuels derived from microalgae. Several value added products of industrial, pharmaceutical and agricultural relevance could be simultaneously derived from microalgae during bioenergy production. Despite these value-added products having the potential to offset the high cost of downstream processing of renewable fuels, their production has not been explored in-depth. This review presents a critical overview of the current state of biotechnological applications of microalgae for human benefit and highlights possible areas for further research and development. 相似文献
103.
Kuyper M Toirkens MJ Diderich JA Winkler AA van Dijken JP Pronk JT 《FEMS yeast research》2005,5(10):925-934
We have recently reported about a Saccharomyces cerevisiae strain that, in addition to the Piromyces XylA xylose isomerase gene, overexpresses the native genes for the conversion of xylulose to glycolytic intermediates. This engineered strain (RWB 217) exhibited unprecedentedly high specific growth rates and ethanol production rates under anaerobic conditions with xylose as the sole carbon source. However, when RWB 217 was grown on glucose-xylose mixtures, a diauxic growth pattern was observed with a relatively slow consumption of xylose in the second growth phase. After prolonged cultivation in an anaerobic, xylose-limited chemostat, a culture with improved xylose uptake kinetics was obtained. This culture also exhibited improved xylose consumption in glucose-xylose mixtures. A further improvement in mixed-sugar utilization was obtained by prolonged anaerobic cultivation in automated sequencing-batch reactors on glucose-xylose mixtures. A final single-strain isolate (RWB 218) rapidly consumed glucose-xylose mixtures anaerobically, in synthetic medium, with a specific rate of xylose consumption exceeding 0.9 gg(-1)h(-1). When the kinetics of zero trans-influx of glucose and xylose of RWB 218 were compared to that of the initial strain, a twofold higher capacity (V(max)) as well as an improved K(m) for xylose was apparent in the selected strain. It is concluded that the kinetics of xylose fermentation are no longer a bottleneck in the industrial production of bioethanol with yeast. 相似文献
104.
Khambhaty Y Mody K Gandhi MR Thampy S Maiti P Brahmbhatt H Eswaran K Ghosh PK 《Bioresource technology》2012,103(1):180-185
The present study describes production of bio-ethanol from fresh red alga, Kappaphycus alvarezii. It was crushed to expel sap - a biofertilizer - while residual biomass was saccharified at 100 °C in 0.9 N H2SO4. The hydrolysate was repeatedly treated with additional granules to achieve desired reducing sugar concentration. The best yields for saccharification, inclusive of sugar loss in residue, were 26.2% and 30.6% (w/w) at laboratory (250 g) and bench (16 kg) scales, respectively. The hydrolysate was neutralized with lime and the filtrate was desalted by electrodialysis. Saccharomyces cerevisiae (NCIM 3523) was used for ethanol production from this non-traditional bio-resource. Fermentation at laboratory and bench scales converted ca. 80% of reducing sugar into ethanol in near quantitative selectivity. A petrol vehicle was successfully run with E10 gasoline made from the seaweed-based ethanol. Co-production of ethanol and bio-fertilizer from this seaweed may emerge as a promising alternative to land-based bio-ethanol. 相似文献
105.
There is considerable interest in recent years in the bioconversion of forestry and agricultural residues into ethanol and value-added chemicals. High ethanol yields from lignocellulosic residues are dependent on efficient use of all the available sugars including glucose and xylose. The well-known fermentative yeast Saccharomyces cerevisiae is the preferred microorganism for ethanol production, but unfortunately, this yeast is unable to ferment xylose. Over the last 15 years, this yeast has been the subject of various research efforts aimed at improving its ability to utilize xylose and ferment it to ethanol. This review examines the research on S. cerevisiae strains that have been genetically modified or adapted to ferment xylose to ethanol. The current state of these efforts and areas where further research is required are identified and discussed. 相似文献
106.
A central composite design of response surface method was used to optimize H2SO4-catalyzed hydrothermal pretreatment of rapeseed straw, in respect to acid concentration (0.5–2%), treatment time (5–20 min) and solid content (10–20%) at 180 °C. Enzymatic hydrolysis and fermentation were also measured to evaluate the optimal pretreatment conditions for maximizing ethanol production. The results showed that acid concentration and treatment time were more significant than solid content for optimization of xylose release and cellulose recovery. Pretreatment with 1% sulfuric acid and 20% solid content for 10 min at 180 °C was found to be the most optimal condition for pretreatment of rapeseed straw for ethanol production. After pretreatment at the optimal condition and enzymatic hydrolysis, 75.12% total xylan and 63.17% total glucan were converted to xylose and glucose, respectively. Finally, 66.79% of theoretical ethanol yielded after fermentation. 相似文献
107.
A simple method for determining bioethanol content in gasoline containing bioethanol (denoted as E-gasoline in this study) is urgently required. Liquid scintillation counting (LSC) was employed based on the principle that 14C exists in bioethanol but not in synthetic ethanol. Bioethanol was extracted in two steps by water from E-gasoline containing 3% (E3) or 10% (E10) bioethanol. The 14C radioactivity was measured by LSC and converted to the amount of bioethanol. The bioethanol content in E-gasoline was determined precisely from the partition coefficient in the extraction and the amount of bioethanol in the water phases: 2.98 ± 0.10% for E3 and 10.0 ± 0.1% for E10 (means ± SD; n = 3). It appears that this method can be used to determine bioethanol content in E-gasoline quickly and easily. 相似文献
108.
Tomoko Shimokawa Mutumi Ishida Shigeki Yoshida Masanobu Nojiri 《Bioresource technology》2009,100(24):6651-6654
Bamboo is a fast-growing renewable biomass that is widely distributed in Asia. Although bamboo is recognised as a useful resource, its utilization is limited and further development is required. Immature bamboo shoots harvested before branch spread were found to be a good biomass resource to achieve a high saccharification yield. The saccharification yield of the shoots increased (up to 98% for immature Phyllostachys bambusoides) when xylanase was used in addition to cellulase. Simultaneous saccharification and fermentation (SSF) processing converted immature shoots of P. bambusoides and Phyllostachys pubescens to ethanol with an ethanol yield of 169 and 139 g kg−1, respectively (98% and 81%, respectively, of the theoretical yields based on hexose conversion) when 12 FPU g−1 enzyme and the yeast Saccharomyces cerevisiae were used. 相似文献
109.
110.
The aims of this research were to investigate the potential for improvement of bioethanol fermentation by microwave pre-treatment of triticale, as well as the possibility of using triticale stillage (a by-product of bioethanol fermentation) as a suitable medium for lactic acid fermentation, either without or with the optimal addition of CaCO3. The results showed that an adequate microwave pre-treatment (270 and 450 W) marginally improved bioethanol production, giving a slightly higher yield of the bioethanol produced (by 3.95%). Lactobacillus fermentum PL-1 was used for subsequent lactic acid fermentation of the stillage that remained after bioethanol fermentation. Results showed higher pH decrease and higher acidity in the samples without the addition of CaCO3. Consequently, higher concentrations of l- and d-lactic acid were determined in the samples with the addition of CaCO3, as well as better viability of cells and the complete glucose utilization. 相似文献