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1.
A very high gravity (VHG) repeated-batch fermentation system using an industrial strain of Saccharomyces cerevisiae PE-2 (isolated from sugarcane-to-ethanol distillery in Brazil) and mimicking industrially relevant conditions (high inoculation
rates and low O2 availability) was successfully operated during fifteen consecutive fermentation cycles, attaining ethanol at 17.1 ± 0.2%
(v/v) with a batch productivity of 3.5 ± 0.04 g l−1 h−1. Moreover, this innovative operational strategy (biomass refreshing step) prevented critical decreases on yeast viability
levels and promoted high accumulation of intracellular glycerol and trehalose, which can provide an adaptive advantage to
yeast cells under harsh industrial environments. This study contributes to the improvement of VHG fermentation processes by
exploring an innovative operational strategy that allows attaining very high ethanol titres without a critical decrease of
the viability level thus minimizing the production costs due to energy savings during the distillation process. 相似文献
2.
Ni-Ni Guo Zong-Ming Zheng Yu-Lin Mai Hong-Juan Liu De-Hua Liu 《Applied microbiology and biotechnology》2010,86(2):701-707
The filtration in 1,3-propanediol (1,3-PD) downstream process is influenced by the large amounts of capsular polysaccharides
(CPS) produced by Klebsiella pneumoniae CGMCC 1.6366. The morphological and fermentation properties were investigated with the CPS-deficient mutant K. pneumoniae CGMCC 1.6366 CPS. Similar biomass was obtained with CGMCC 1.6366, and the mutant strain in batch cultures indicating the
cell growth was slightly inhibited by CPS defection. The viscosity of fermentation broth by mutant strain decreased by 27.45%.
The flux with ceramic membrane filter was enhanced from 168.12 to 303.6 l h−1 m−2, exhibiting the great importance for downstream processing of 1,3-PD fermentation. The products spectrum of mutant isolate
changed remarkably regarding to the concentration of fermentation products. The synthesis of important 1,3-PD and 2,3-butanediol
was enhanced from 9.73 and 4.06 g l−1 to 10.37 and 4.77 g l−1 in batch cultures. The noncapsuled K. pneumoniae provided higher 1,3-PD yield of 0.54 mol mol−1 than that of encapsuled wild parent in batch cultures. The fed-batch fermentation of mutant strain resulted in 1,3-PD concentration,
yield, and productivity of 78.13 g l−1, 0.53 mol mol−1, and 1.95 g l−1 h−1, respectively. 相似文献
3.
Using the recombinant flocculating Angel yeast F6, long-term repeated batch fermentation for ethanol production was performed
and a high volumetric productivity resulted from half cells not washed and the optimum opportunity of residual glucose 20
g l−1 of last medium. The obtained highest productivity was 2.07 g l−1 h−1, which was improved by 75.4% compared with that of 1.18 g l−1 h−1 in the first batch fermentation. The ethanol concentration reached 8.4% corresponding to the yield of 0.46 g g−1. These results will contribute greatly to the industrial production of fuel ethanol using the commercial method with the
flocculating yeast. 相似文献
4.
The fermentation characteristics of the novel, thermotolerant, isolate Kluyveromyces marxianus var marxianus were determined to evaluate its aptitude for use in an ethanol production process. Sustainable growth was not observed under
anaerobic conditions, even in the presence of unsaturated fatty acid and sterol. A maximum ethanol concentration of 40 g L−1 was produced at 45°C, with an initial specific ethanol production rate of 1.7 g g−1 h−1. This was observed at ethanol concentrations below 8 g L−1 and under oxygen-limited conditions. The low ethanol tolerance and low growth under oxygen-limited conditions required for
ethanol production implied that a simple continuous process was not feasible with this yeast strain. Improved productivity
was achieved through recycling biomass into the fermenter, indicating that utilising an effective cell retention method such
as cell recycle or immobilisation, could lead to the development of a viable industrial process using this novel yeast strain.
Received 14 February 1998/ Accepted in revised form 19 May 1998 相似文献
5.
N Kiran Sree M Sridhar K Suresh I M Banat L Venkateswar Rao 《Journal of industrial microbiology & biotechnology》2000,24(3):222-226
A repeated batch fermentation system was used to produce ethanol using an osmotolerant Saccharomyces cerevisiae (VS3) immobilized in calcium alginate beads. For comparison free cells were also used to produce ethanol by repeated batch fermentation.
Fermentation was carried for six cycles with 125, 250 or 500 beads using 150, 200 or 250 g glucose L−1 at 30°C. The maximum amount of ethanol produced by immobilized VS3 using 150 g L−1 glucose was only 44 g L−1 after 48 h, while the amount of ethanol produced by free cells in the first cycle was 72 g L−1. However in subsequent fed batch cultures more ethanol was produced by immobilized cells compared to free cells. The amount
of ethanol produced by free cells decreased from 72 g L−1 to 25 g L−1 after the fourth cycle, while that of immobilized cells increased from 44 to 72 g L−1. The maximum amount of ethanol produced by immobilized VS3 cells using 150, 200 and 250 g glucose L−1 was 72.5, 93 and 87 g ethanol L−1 at 30°C. Journal of Industrial Microbiology & Biotechnology (2000) 24, 222–226.
Received 16 September 1999/ Accepted in revised form 22 December 1999 相似文献
6.
Compared with steady state, oscillation in continuous very-high-gravity ethanol fermentation with Saccharomyces cerevisiae improved process productivity, which was thus introduced for the fermentation system composed of a tank fermentor followed
by four-stage packed tubular bioreactors. When the very-high-gravity medium containing 280 g l−1 glucose was fed at the dilution rate of 0.04 h−1, the average ethanol of 15.8% (v/v) and residual glucose of 1.5 g l−1 were achieved under the oscillatory state, with an average ethanol productivity of 2.14 g h−1 l−1. By contrast, only 14.8% (v/v) ethanol was achieved under the steady state at the same dilution rate, and the residual glucose was as high as 17.1 g l−1, with an ethanol productivity of 2.00 g h−1 l−1, indicating a 7% improvement under the oscillatory state. When the fermentation system was operated under the steady state
at the dilution rate of 0.027 h−1 to extend the average fermentation time to 88 h from 59 h, the ethanol concentration increased slightly to 15.4% (v/v) and residual glucose decreased to 7.3 g l−1, correspondingly, but the ethanol productivity was decreased drastically to 1.43 g h−1 l−1, indicating a 48% improvement under the oscillatory state at the dilution rate of 0.04 h−1. 相似文献
7.
John Chi-Wei Lan Tau Chuan Ling Grant Hamilton Andrew Lyddiatt 《Biotechnology and Bioprocess Engineering》2006,11(5):425-431
The development of fermentation conditions for the production of C595 diabody fragment (dbFv) inE. coli HB2151 clone has been explored. Investigations were carried out to study the effect of carbon supplements over the expression
period, the comparison of C595 dbfv production in synthetic and complex media, the influence of acetic acid upon antibody
production, and comparison of one-stage and two-stage processes operated at batch or fed-batch modes in bioreactor. Yeast
extract supplied during expression yielded more antibody fragment than any other carbon supply. The synthetic medium presented
higher specific productivity (0.066 mg dbFv g−1 dry cell weight) when compared to the complex medium (0.044 mg dbFv g−1 DCW). The comparison of fermentation strategies demonstrated that (1) one-stage fed-batch fermentation performed higher C595
dbFv production than that operated in batch mode which was significantly affected by acetate concentration; (2) a two-stage
batch operation could enhance C595 dbFv production. It was found that a concentration of 12.3 mg L−1 broth of C595 dbFv and a cell concentration of 10.8 g L−1 broth were achieved at the end of two-stage operation in 5-L fermentation. 相似文献
8.
Francisco B. Pereira Pedro M. R. Guimarães José A. Teixeira Lucília Domingues 《Biotechnology letters》2010,32(11):1655-1661
An optimized very high gravity (VHG) glucose medium supplemented with low cost nutrient sources was used to evaluate bio-ethanol
production by 11 Saccharomyces cerevisiae strains. The industrial strains PE-2 and CA1185 exhibited the best overall fermentation performance, producing an ethanol
titre of 19.2% (v/v) corresponding to a batch productivity of 2.5 g l−1 h−1, while the best laboratory strain (CEN.PK 113-7D) produced 17.5% (v/v) ethanol with a productivity of 1.7 g l−1 h−1. The results presented here emphasize the biodiversity found within S. cerevisiae species and that naturally adapted strains, such as PE-2 and CA1185, are likely to play a key role in facilitating the transition
from laboratory technological breakthroughs to industrial-scale bio-ethanol fermentations. 相似文献
9.
Anjali Madhavan Sriappareddy Tamalampudi Aradhana Srivastava Hideki Fukuda Virendra S. Bisaria Akihiko Kondo 《Applied microbiology and biotechnology》2009,82(6):1037-1047
Previously, a Saccharomyces cerevisiae strain was engineered for xylose assimilation by the constitutive overexpression of the Orpinomyces xylose isomerase, the S. cerevisiae xylulokinase, and the Pichia stipitis SUT1 sugar transporter genes. The recombinant strain exhibited growth on xylose, under aerobic conditions, with a specific growth
rate of 0.025 h−1, while ethanol production from xylose was achieved anaerobically. In the present study, the developed recombinant yeast was
adapted for enhanced growth on xylose by serial transfer in xylose-containing minimal medium under aerobic conditions. After
repeated batch cultivations, a strain was isolated which grew with a specific growth rate of 0.133 h−1. The adapted strain could ferment 20 g l−1 of xylose to ethanol with a yield of 0.37 g g−1 and production rate of 0.026 g l−1 h−1. Raising the fermentation temperature from 30°C to 35°C resulted in a substantial increase in the ethanol yield (0.43 g g−1) and production rate (0.07 g l−1 h−1) as well as a significant reduction in the xylitol yield. By the addition of a sugar complexing agent, such as sodium tetraborate,
significant improvement in ethanol production and reduction in xylitol accumulation was achieved. Furthermore, ethanol production
from xylose and a mixture of glucose and xylose was also demonstrated in complex medium containing yeast extract, peptone,
and borate with a considerably high yield of 0.48 g g−1. 相似文献
10.
Cong-fa Yang Zhong-yang Ding Ke-chang Zhang 《World journal of microbiology & biotechnology》2008,24(12):2919-2925
In a cycle tubular photobioreactor, Chlorella pyrenoidosa was cultured in undiluted wastewater from ethanol fermentation using cassava powder as raw material. The results showed that
the optimum cultivation conditions were initial pH of 6.0, temperature at 27°C, continuous illumination at 3,000 lux, and
cycle speed of 110 ml min−1. Under these optimum conditions, after the logarithmic phase of batch cultivation with wastewater of pH 6.0, the reactor
could be continuously operated with natural pH wastewater (3.8) as feed solution. By a dilution ratio of 0.17 day−1, it could be operated stably for over 30 days in continuous cultivation. pH, removal rate of chemical oxygen demand, and
biomass (cell dry weight) concentration ranged from 6.22 to 6.47, 72.21 to 76.32% and 3.55 to 3.73 g l−1, respectively. After treatment, the wastewater could be used again in the process of ethanol fermentation. 相似文献
11.
Sachin Kumar Surendra P. Singh Indra M. Mishra Dilip K. Adhikari 《Journal of industrial microbiology & biotechnology》2009,36(12):1483-1489
A yeast strain Kluyveromyces sp. IIPE453 (MTCC 5314), isolated from soil samples collected from dumping sites of crushed sugarcane bagasse in Sugar Mill,
showed growth and fermentation efficiency at high temperatures ranging from 45°C to 50°C. The yeast strain was able to use
a wide range of substrates, such as glucose, xylose, mannose, galactose, arabinose, sucrose, and cellobiose, either for growth
or fermentation to ethanol. The strain also showed xylitol production from xylose. In batch fermentation, the strain showed
maximum ethanol concentration of 82 ± 0.5 g l−1 (10.4% v/v) on initial glucose concentration of 200 g l−1, and ethanol concentration of 1.75 ± 0.05 g l−1 as well as xylitol concentration of 11.5 ± 0.4 g l−1 on initial xylose concentration of 20 g l−1 at 50°C. The strain was capable of simultaneously using glucose and xylose in a mixture of glucose concentration of 75 g l−1 and xylose concentration of 25 g l−1, achieving maximum ethanol concentration of 38 ± 0.5 g l−1 and xylitol concentration of 14.5 ± 0.2 g l−1 in batch fermentation. High stability of the strain was observed in a continuous fermentation by feeding the mixture of glucose
concentration of 75 g l−1 and xylose concentration of 25 g l−1 by recycling the cells, achieving maximum ethanol concentration of 30.8 ± 6.2 g l−1 and xylitol concentration of 7.35 ± 3.3 g l−1 with ethanol productivity of 3.1 ± 0.6 g l−1 h−1 and xylitol productivity of 0.75 ± 0.35 g l−1 h−1, respectively. 相似文献
12.
In these studies, butanol (acetone butanol ethanol or ABE) was produced from wheat straw hydrolysate (WSH) in batch cultures
using Clostridium beijerinckii P260. In control fermentation 48.9 g L−1 glucose (initial sugar 62.0 g L−1) was used to produce 20.1 g L−1 ABE with a productivity and yield of 0.28 g L−1 h−1 and 0.41, respectively. In a similar experiment where WSH (60.2 g L−1 total sugars obtained from hydrolysis of 86 g L−1 wheat straw) was used, the culture produced 25.0 g L−1 ABE with a productivity and yield of 0.60 g L−1 h−1 and 0.42, respectively. These results are superior to the control experiment and productivity was improved by 214%. When
WSH was supplemented with 35 g L−1 glucose, a reactor productivity was improved to 0.63 g L−1 h−1 with a yield of 0.42. In this case, ABE concentration in the broth was 28.2 g L−1. When WSH was supplemented with 60 g L−1 glucose, the resultant medium containing 128.3 g L−1 sugars was successfully fermented (due to product removal) to produce 47.6 g L−1 ABE, and the culture utilized all the sugars (glucose, xylose, arabinose, galactose, and mannose). These results demonstrate
that C. beijerinckii P260 has excellent capacity to convert biomass derived sugars to solvents and can produce over 28 g L−1 (in one case 41.7 g L−1 from glucose) ABE from WSH. Medium containing 250 g L−1 glucose resulted in no growth and no ABE production. Mixtures containing WSH + 140 g L−1 glucose (total sugar approximately 200 g L−1) showed poor growth and poor ABE production.
Mention of trade names or commercial products in this article is solely for the purpose of providing scientific information
and does not imply recommendation or endorsement by the United States Department of Agriculture. 相似文献
13.
Analysis and optimization of a two-substrate fermentation for xylitol production using Candida tropicalis 总被引:1,自引:0,他引:1
Xylitol, a functional sweetener, was produced from xylose using Candida tropicalisATCC 13803. A two-substrate fermentation was designed in order to increase xylitol yield and volumetric productivity. Glucose
was used initially for cell growth followed by conversion of xylose to xylitol without cell growth and by-product formation
after complete depletion of glucose. High glucose concentrations increased volumetric productivity by reducing conversion
time due to high cell mass, but also led to production of ethanol, which, in turn, inhibited cell growth and xylitol production.
Computer simulation was undertaken to optimize an initial glucose concentration using kinetic equations describing rates of
cell growth and xylose bioconversion as a function of ethanol concentration. Kinetic constants involved in the equations were
estimated from the experimental results. Glucose at 32 g L−1 was estimated to be an optimum initial glucose concentration with a final xylose concentration of 86 g L−1 and a volumetric productivity of 5.15 g-xylitol L−1 h−1. The two-substrate fermentation was performed under optimum conditions to verify the computer simulation results. The experimental
results were in good agreement with the predicted values of simulation with a xylitol yield of 0.81 g-xylitol g-xylose−1 and a volumetric productivity of 5.06 g-xylitol L−1 h−1.
Received 16 June 1998/ Accepted in revised form 28 February 1999 相似文献
14.
Vlada B. Veljković Miodrag L. Lazić Mihajlo Z. Stanković 《World journal of microbiology & biotechnology》2006,22(5):519-523
Summary The object of this study was to establish the possibility of using the yeast biomass separated from the fermentation broth
at the end of ethanol fermentation of juniper berry sugars as an inoculum in successive batch fermentation processes. A part
of the fermentation broth (10% v/v) and a suspension of yeast biomass (separated from the same broth) into the water extract
of juniper berries (2 g of wet yeast biomass per liter of water extract) were used as inocula. It was shown that the suspension
of yeast biomass could be used as inoculum in successive batch processes without negative effects on the kinetics and ethanol
yield, but with positive effects on the capacity and economy of the bioprocess. The addition of ammonium salts at optimum
levels did not affect the final ethanol concentrations (4.3–4.4% v/v), but enhanced the specific rate of ethanol production,
thus reducing the process duration by about five times. 相似文献
15.
Téllez-Téllez M Fernández FJ Montiel-González AM Sánchez C Díaz-Godínez G 《Applied microbiology and biotechnology》2008,81(4):675-679
Pleurotus ostreatus showed atypical laccase production in submerged vs. solid-state fermentation. Cultures grown in submerged fermentation produced
laccase at 13,000 U l−1, with a biomass production of 5.6 g l−1 and four laccase isoforms. However, cultures grown in solid-state fermentation had a much lower laccase activity of 2,430 U
l−1, biomass production of 4.5 g l−1, and three laccase isoforms. These results show that P. ostreatus performs much better in submerged fermentation than in solid-state fermentation. This is the first report that shows such
atypical behavior in the production of extracellular laccases by fungi. 相似文献
16.
Naresh Sharma K. L. Kalra Harinder Singh Oberoi Sunil Bansal 《Indian journal of microbiology》2007,47(4):310-316
A study was taken up to evaluate the role of some fermentation parameters like inoculum concentration, temperature, incubation
period and agitation time on ethanol production from kinnow waste and banana peels by simultaneous saccharification and fermentation
using cellulase and co-culture of Saccharomyces cerevisiae G and Pachysolen tannophilus MTCC 1077. Steam pretreated kinnow waste and banana peels were used as substrate for ethanol production in the ratio 4:6
(kinnow waste: banana peels). Temperature of 30°C, inoculum size of S. cerevisiae G 6% and (v/v) Pachysolen tannophilus MTCC 1077 4% (v/v), incubation period of 48 h and agitation for the first 24 h were found to be best for ethanol production
using the combination of two wastes. The pretreated steam exploded biomass after enzymatic saccharification containing 63
gL−1 reducing sugars was fermented with both hexose and pentose fermenting yeast strains under optimized conditions resulting
in ethanol production, yield and fermentation efficiency of 26.84 gL−1, 0.426 gg −1 and 83.52 % respectively. This study could establish the effective utilization of kinnow waste and banana peels for bioethanol
production using optimized fermentation parameters. 相似文献
17.
Lakkana Laopaiboon Pornthap Thanonkeo Prasit Jaisil Pattana Laopaiboon 《World journal of microbiology & biotechnology》2007,23(10):1497-1501
Sweet sorghum juice supplemented with 0.5% ammonium sulphate was used as a substrate for ethanol production by Saccharomyces cerevisiae TISTR 5048. In batch fermentation, kinetic parameters for ethanol production depended on initial cell and sugar concentrations.
The optimum initial cell and sugar concentrations in the batch fermentation were 1 × 108 cells ml−1 and 24 °Bx respectively. At these conditions, ethanol concentration produced (P), yield (Y
ps) and productivity (Q
p
) were 100 g l−1, 0.42 g g−1 and 1.67 g l−1 h−1 respectively. In fed-batch fermentation, the optimum substrate feeding strategy for ethanol production at the initial sugar
concentration of 24 °Bx was one-time substrate feeding, where P, Y
ps and Q
p
were 120 g l−1, 0.48 g g−1 and 1.11 g l−1 h−1 respectively. These findings suggest that fed-batch fermentation improves the efficiency of ethanol production in terms of
ethanol concentration and product yield. 相似文献
18.
Batch cultivation of Ralstonia eutropha NRRL B14690 attained 21 g biomass l−1 and 9.4 g poly(β-hydroxybutyrate) l−1 (0.45 g PHB g−1 dry wt−1) in 60 h. Repeated batch operation (empty-and-fill protocol) to remove 20% (v/v) of the culture broth and to supplement an
equal volume of fresh media resulted in 49 g biomass l−1 and 25 g PHB l−1 (0.51 g PHB g−1 dry wt−1) with an overall productivity of 0.42 g PHB l−1 h−1 in 67 h. In the two cycles of repeated batch fermentation there was a 3-fold increase in productivity as compared to batch. 相似文献
19.
Khanh Dang Vu Rajeshwar Dayal Tyagi José R. Valéro Rao Y. Surampalli 《Bioprocess and biosystems engineering》2010,33(6):691-700
Bacillus thuringiensis var. kurstaki biopesticide was produced in batch and fed-batch fermentation modes using starch industry wastewater as sole substrate. Fed-batch
fermentation with two intermittent feeds (at 10 and 20 h) during the fermentation of 72 h gave the maximum delta-endotoxin
concentration (1,672.6 mg/L) and entomotoxicity (Tx) (18.5 × 106 SBU/mL) in fermented broth which were significantly higher than maximum delta-endotoxin concentration (511.0 mg/L) and Tx
(15.8 × 106 SBU/mL) obtained in batch process. However, fed-batch fermentation with three intermittent feeds (at 10, 20 and 34 h) of
the fermentation resulted in the formation of asporogenous variant (Spo−) from 36 h to the end of fermentation (72 h) which
resulted in a significant decrease in spore and delta-endotoxin concentration and finally the Tx value. Tx of suspended pellets
(27.4 × 106 SBU/mL) obtained in fed-batch fermentation with two feeds was the highest value as compared to other cases. 相似文献
20.
In this paper, a downstream process for purification of 1,3-propanediol from glycerol-based fermentation broth was investigated.
The purification of 1,3-propanediol from fermentation broth was achieved by a process combining microfiltration, charcoal
treatment, vacuum distillation, and silica gel chromatography. The broth was first filtered through hollow fiber cartridge,
wherein 98.7% of biomass was removed. Soluble proteins and other color impurities in the broth were removed by the use of
activated charcoal at optimal concentration of 30 g l−1 where the soluble proteins in the broth decreased to 0.1 g l−1 (96.0% protein loss). The obtained broth when concentrated by vacuum distillation resulted in the crystallization of inorganic
salts. Subsequently, 1,3-propanediol was purified by gradient chromatography using silica gel as a stationary phase and mixture
of chloroform and methanol as a mobile phase. Finally, with the optimal flow rate of 10 ml min−1 and loading amount of 80 ml, the yield of 1,3-propanediol achieved was 89%. The overall yield of 1,3-propanediol using the
proposed procedure was 75.47%. The developed method was found to be a simple, rapid, and efficient procedure for the purification
of 1,3-propanediol from fermentation broth. 相似文献