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1.
An innovative consecutive batch fermentation process for very high gravity ethanol fermentation with self-flocculating yeast 总被引:1,自引:0,他引:1
An innovative consecutive batch fermentation process was developed for very high gravity (VHG) ethanol fermentation with the
self-flocculating yeast under high biomass concentration conditions. On the one hand, the high biomass concentration significantly
shortened the time required to complete the VHG fermentation and the duration of yeast cells suffering from strong ethanol
inhibition, preventing them from losing viability and making them suitable for being repeatedly used in the process. On the
other hand, the separation of yeast cells from the fermentation broth by sedimentation instead of centrifugation, making the
process economically more competitive. The VHG medium composed of 255 g L−1 glucose and 6.75 g L−1 each of yeast extract and peptone was fed into the fermentation system for nine consecutive batch fermentations, which were
completed within 8–14 h with an average ethanol concentration of 15% (v/v) and ethanol yield of 0.464, 90.8% of its theoretical value of 0.511. The average ethanol productivity that was calculated
with the inclusion of the downstream time for the yeast flocs to settle from the fermentation broth and the supernatant to
be removed from the fermentation system was 8.2 g L−1 h−1, much higher than those previously reported for VHG ethanol fermentation and regular ethanol fermentation with ethanol concentration
around 12% (v/v) as well. 相似文献
2.
Apiwatanapiwat W Murata Y Kosugi A Yamada R Kondo A Arai T Rugthaworn P Mori Y 《Applied microbiology and biotechnology》2011,90(1):377-384
In order to develop a method for producing fuel ethanol from cassava pulp using cell surface engineering (arming) technology,
an arming yeast co-displaying α-amylase (α-AM), glucoamylase, endoglucanase, cellobiohydrase, and β-glucosidase on the surface
of the yeast cells was constructed. The novel yeast strain, possessing the activities of all enzymes, was able to produce
ethanol directly from soluble starch, barley β-glucan, and acid-treated Avicel. Cassava is a major crop in Southeast Asia
and used mainly for starch production. In the starch manufacturing process, large amounts of solid wastes, called cassava
pulp, are produced. The major components of cassava pulp are starch (approximately 60%) and cellulose fiber (approximately
30%). We attempted simultaneous saccharification and ethanol fermentation of cassava pulp with this arming yeast. During fermentation,
ethanol concentration increased as the starch and cellulose fiber substrates contained in the cassava pulp decreased. The
results clearly showed that the arming yeast was able to produce ethanol directly from cassava pulp without addition of any
hydrolytic enzymes. 相似文献
3.
Fermentation of high concentrations of lactose to ethanol by engineered flocculent Saccharomyces cerevisiae 总被引:1,自引:0,他引:1
The development of microorganims that efficiently ferment lactose has a high biotechnological interest, particularly for cheese
whey bioremediation processes with simultaneous bio-ethanol production. The lactose fermentation performance of a recombinant
Saccharomyces cerevisiae flocculent strain was evaluated. The yeast consumed rapidly and completely lactose concentrations up to 150 g l−1 in either well- or micro-aerated batch fermentations. The maximum ethanol titre was 8% (v/v) and the highest ethanol productivity
was 1.5–2 g l−1 h−1, in micro-aerated fermentations. The results presented here emphasise that this strain is an interesting alternative for
the production of ethanol from lactose-based feedstocks. 相似文献
4.
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
5.
Okano K Kimura S Narita J Fukuda H Kondo A 《Applied microbiology and biotechnology》2007,75(5):1007-1013
To achieve direct and efficient lactic acid production from starch, a genetically modified Lactococcus lactis IL 1403 secreting α-amylase, which was obtained from Streptococcus bovis 148, was constructed. Using this strain, the fermentation of soluble starch was achieved, although its rate was far from
efficient (0.09 g l−1 h−1 lactate). High-performance liquid chromatography revealed that maltose accumulated during fermentation, and this was thought
to lead to inefficient fermentation. To accelerate maltose consumption, starch fermentation was examined using L. lactis cells adapted to maltose instead of glucose. This led to a decrease in the amount of maltose accumulation in the culture,
and, as a result, a more rapid fermentation was accomplished (1.31 g l−1 h−1 lactate). Maximum volumetric lactate productivity was further increased (1.57 g l−1 h−1 lactate) using cells adapted to starch, and a high yield of lactate (0.89 g of lactate per gram of consumed sugar) of high
optical purity (99.2% of l-lactate) was achieved. In this study, we propose a new approach to lactate production by α-amylase-secreting L. lactis that allows efficient fermentation from starch using cells adapted to maltose or starch before fermentation. 相似文献
6.
《Journal of Fermentation and Bioengineering》1990,69(4):228-233
Direct ethanol production from raw starch was performed continuously using a combination of a reversibly soluble-autoprecipitating amylase (D-AS) in which Dabiase K-27 was immobilized covalently on an enteric coating polymer (hydroxypropyl methylcellulose acetate succinate, AS) as a carrier, and a flocculating yeast. Continuous production was carried out using a reactor equipped with a mixing vessel and a separation vessel. D-AS and the yeast were separated continuously from the product solution by self-sedimentation in the separation vessel and they were utilized repeatedly. In the continuous saccharification of raw starch by D-AS alone, the glucose productivity was about 3.6 g/l/h at a dilution rate (D) of 0.1 h−1. In the continuous ethanol production from raw starch by a combination of D-AS and flocculating yeast cells, high ethanol productivity up to 2.0 g/l/h was achieved at D=0.1 h−1. Although the enzymatic activity of D-AS is inactivated due to insolubilization of the enzyme by the accumulation of NaCl produced in controlling the pH in the reactor, it is possible to recover the D-AS enzymatic activity by removing the NaCl. This continuous fermentation system suggests a potential for effective ethanol production from raw starch, and it may be widely applicable in heterogeneous culture systems using solid substrates other than raw starch. 相似文献
7.
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
8.
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
9.
Lactic acid production was investigated for batch and repeated batch cultures of Enterococcus faecalis RKY1, using wood hydrolyzate and corn steep liquor. When wood hydrolyzate (equivalent to 50 g l−1 glucose) supplemented with 15–60 g l−1 corn steep liquor was used as a raw material for fermentation, up to 48.6 g l−1 of lactic acid was produced with, volumetric productivities ranging between 0.8 and 1.4 g l−1 h−1. When a medium containing wood hydrolyzate and 15 g l−1 corn steep liquor was supplemented with 1.5 g l−1 yeast extract, we observed 1.9-fold and 1.6-fold increases in lactic acid productivity and cell growth, respectively. In this case, the nitrogen source cost for producing 1 kg lactic acid can be reduced to 23% of that for fermentation from wood hydrolyzate using 15 g l−1 yeast extract as a single nitrogen source. In addition, lactic acid productivity could be maximized by conducting a cell-recycle repeated batch culture of E. faecalis RKY1. The maximum productivity for this process was determined to be 4.0 g l−1 h−1. 相似文献
10.
Churairat Moukamnerd Masahiro Kino-oka Minetaka Sugiyama Yoshinobu Kaneko Chuenchit Boonchird Satoshi Harashima Hideo Noda Kazuaki Ninomiya Suteaki Shioya Yoshio Katakura 《Applied microbiology and biotechnology》2010,88(1):87-94
To save cost and input energy for bioethanol production, a consolidated continuous solid-state fermentation system composed
of a rotating drum reactor, a humidifier, and a condenser was developed. Biomass, saccharifying enzymes, yeast, and a minimum
amount of water are introduced into the system. Ethanol produced by simultaneous saccharification and fermentation is continuously
recovered as vapor from the headspace of the reactor, while the humidifier compensates for the water loss. From raw corn starch
as a biomass model, 95 ± 3, 226 ± 9, 458 ± 26, and 509 ± 64 g l−1 of ethanol solutions were recovered continuously when the ethanol content in reactor was controlled at 10–20, 30–50, 50–70
and 75–85 g kg-mixture−1, respectively. The residue showed a lesser volume and higher solid content than that obtained by conventional liquid fermentation.
The cost and energy for intensive waste water treatment are decreased, and the continuous fermentation enabled the sustainability
of enzyme activity and yeast in the system. 相似文献
11.
Taking continuous ethanol fermentation with the self‐flocculating yeast SPSC01 under very high concentration conditions as an example, the fermentation performance of the yeast flocs and their metabolic flux distribution were investigated by controlling their average sizes at 100, 200, and 300 µm using the focused beam reflectance online measurement system. In addition, the impact of zinc supplementation was evaluated for the yeast flocs at the size of 300 µm grown in presence or absence of 0.05 g L?1 zinc sulfate. Among the yeast flocs with different sizes, the group with the average size of 300 µm exhibited highest ethanol production (110.0 g L?1) and glucose uptake rate (286.69 C mmol L?1 h?1), which are in accordance with the increased flux from pyruvate to ethanol and decreased flux to glycerol. And in the meantime, zinc supplementation further increased ethanol production and cell viability comparing with the control. Zinc addition enhanced the carbon fluxes to the biosynthesis of ergosterol (28.6%) and trehalose (43.3%), whereas the fluxes towards glycerol, protein biosynthesis, and tricarboxylic acid cycle significantly decreased by 37.7%, 19.5%, and 27.8%, respectively. This work presents the first report on the regulation of metabolic flux by the size of yeast flocs and zinc supplementation, which provides the potential for developing engineering strategy to optimize the fermentation system. Biotechnol. Bioeng. 2010;105: 935–944. © 2009 Wiley Periodicals, Inc. 相似文献
12.
Mucor indicus can be used to produce ethanol from a variety of sugars, including pentose’s. An extract of it, produced by autolysis, could
replace yeast extract in culture medium with improved production of ethanol. At 10 g l−1, the extract gave a higher ethanol yield (0.47 g g−1) and productivity (0.71 g l−1 h−1) compared to medium containing yeast extract (yield 0.45 g g−1; productivity 0.67 g l−1 h−1). 相似文献
13.
Production of butanol from starch-based waste packing peanuts and agricultural waste 总被引:3,自引:0,他引:3
Jesse TW Ezeji TC Qureshi N Blaschek HP 《Journal of industrial microbiology & biotechnology》2002,29(3):117-123
We examined the fermentation of starch-based packing peanuts and agricultural wastes as a source of fermentable carbohydrates
using Clostridium beijerinckii BA101. Using semidefined P2 medium containing packing peanuts and agricultural wastes, instead of glucose as a carbohydrate
source, we measured characteristics of the fermentation including solvent production, productivity, and yield. With starch
as substrate (control), the culture produced 24.7 g l−1 acetone–butanol–ethanol (ABE), while with packing peanuts it produced 21.7 g l−1 total ABE with a productivity of 0.20 g l−1 h−1 and a solvent (ABE) yield of 0.37. Cell growth in starch, packing peanuts, and agricultural wastes medium was different,
possibly due to the different nature of these substrates. Using model agricultural waste, 20.3g l−1 ABE was produced; when using actual waste, 14.8 g l−1 ABE was produced. The use of inexpensive substrates will increase the economic viability of the conversion of biomass to
butanol, and can provide new markets for these waste streams. Journal of Industrial Microbiology & Biotechnology (2002) 29, 117–123 doi: 10.1038/sj.jim.7000285
Received 14 November 2001/ Accepted in revised form 07 June 2002 相似文献
14.
Comparison of SHF and SSF processes for the bioconversion of steam-exploded wheat straw 总被引:6,自引:0,他引:6
F Alfani A Gallifuoco A Saporosi A Spera M Cantarella 《Journal of industrial microbiology & biotechnology》2000,25(4):184-192
Two processes for ethanol production from wheat straw have been evaluated — separate hydrolysis and fermentation (SHF) and
simultaneous saccharification and fermentation (SSF). The study compares the ethanol yield for biomass subjected to varying
steam explosion pretreatment conditions: temperature and time of pretreatment was 200°C or 217°C and at 3 or 10 min. A rinsing
procedure with water and NaOH solutions was employed for removing lignin residues and the products of hemicellulose degradation
from the biomass, resulting in a final structure that facilitated enzymatic hydrolysis. Biomass loading in the bioreactor
ranged from 25 to 100 g l−1 (dry weight). The enzyme-to-biomass mass ratio was 0.06. Ethanol yields close to 81% of theoretical were achieved in the
two-step process (SHF) at hydrolysis and fermentation temperatures of 45°C and 37°C, respectively. The broth required addition
of nutrients. Sterilisation of the biomass hydrolysate in SHF and of reaction medium in SSF can be avoided as can the use
of different buffers in the two stages. The optimum temperature for the single-step process (SSF) was found to be 37°C and
ethanol yields close to 68% of theoretical were achieved. The SSF process required a much shorter overall process time (≈30
h) than the SHF process (96 h) and resulted in a large increase in ethanol productivity (0.837 g l−1 h−1 for SSF compared to 0.313 g l−1 h−1 for SHF). Journal of Industrial Microbiology & Biotechnology (2000) 25, 184–192.
Received 02 December 1999/ Accepted in revised form 20 July 2000 相似文献
15.
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
16.
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
17.
Industrial strains of a polyploid, distiller’s Saccharomyces cerevisiae that produces glucoamylase and α-amylase was used for the direct fermentation of raw starch to ethanol. Strains contained
either Aspergillus awamori glucoamylase gene (GA1), Debaryomyces occidentalis glucoamylase gene (GAM1) or D. occidentalis α-amylase gene (AMY), singly or in combination, integrated into their chromosomes. The strain expressing both GA1 and AMY generated 10.3% (v/v) ethanol (80.9 g l−1) from 20% (w/v) raw corn starch after 6 days of fermentation, and decreased the raw starch content to 21% of the initial
concentration. 相似文献
18.
Viable Saccharomyces cerevisiae and Candida shehatae cells were co-immobilized in a composite agar layer/microporous membrane structure. This immobilized-cell structure was placed
in a vertical position between the two halves of a double-chambered, stainless-steel bioreactor of original design and applied
to the continuous alcoholic fermentation of a mixture of glucose (35 g dm−3) and xylose (15 g dm−3). Various dilution rates and initial cell loadings of the gel layer were tested. Simultaneous consumption of the two sugars
was always observed. The best fermentation performance was obtained at low dilution rate (0.02 h−1) with an excess of C. shehatae over S. cerevisiae in the initial cell loading of the gel (5.0 mg dry weight and 0.65 mg dry weight cm−3 gel respectively): 100% of glucose and 73% of xylose were consumed with an ethanol yield coefficient of 0.48 g g total sugars−1. In these conditions, however, the ethanol production rate per unit volume of gel remained low (0.37 g h−1 dm−3). Viable cell counts in gel samples after incubation highlighted significant heterogeneities in the spatial distribution
of the two yeast species in both the vertical and the transverse directions. In particular, the overall cell number decreased
from the bottom to the top of the agar sheet, which may explain the low ethanol productivity relative to the total gel volume.
Received: 26 February 1998 / Received revision: 15 April 1998 / Accepted: 19 April 1998 相似文献
19.
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
20.
Ezeji TC Qureshi N Blaschek HP 《Journal of industrial microbiology & biotechnology》2007,34(12):771-777
A potential industrial substrate (liquefied corn starch; LCS) has been employed for successful acetone butanol ethanol (ABE)
production. Fermentation of LCS (60 g l−1) in a batch process resulted in the production of 18.4 g l−1 ABE, comparable to glucose: yeast extract based medium (control experiment, 18.6 g l−1 ABE). A batch fermentation of LCS integrated with product recovery resulted in 92% utilization of sugars present in the feed.
When ABE was recovered by gas stripping (to relieve inhibition) from the fed-batch reactor fed with saccharified liquefied
cornstarch (SLCS), 81.3 g l−1 ABE was produced compared to 18.6 g l−1 (control). In this integrated system, 225.8 g l−1 SLCS sugar (487 % of control) was consumed. In the absence of product removal, it is not possible for C. beijerinckii BA101 to utilize more than 46 g l−1 glucose. A combination of fermentation of this novel substrate (LCS) to butanol together with product recovery by gas stripping
may economically benefit this fermentation.
Mention of trade names of commercial products in this article/publication 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