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1.
In this study, we found that Rhodotorula mucilaginosa TJY15a could accumulate 48.8% (w/w) oil from hydrolysate of inulin and its cell dry weight reached 14.8 g/l during the batch cultivation while it could accumulate 48.6% (w/w) oil and 52.2% (w/w) oil from hydrolysate of extract of Jerusalem artichoke tubers and its cell dry weight reached 14.4 g/l and 19.5 g/l during the batch and fed-batch cultivations, respectively. At the end of the fed-batch cultivation, only 0.04% of reducing sugar and 0.08% of total sugar were left in the fermented medium. Over 87.6% of the fatty acids from the yeast strain TJY15a cultivated in the hydrolysate of extract of Jerusalem artichoke tubers was C 16:0, C 18:1 and C 18:2, especially C 18:1 (54.7%). Therefore, the results show that hydrolysates of inulin and extract of Jerusalem artichoke tubers were also the good materials for single cell oil production. 相似文献
2.
Sugar maple hemicellulosic hydrolysate containing 71.9 g/l of xylose was used as an inexpensive feedstock to produce polyhydroxyalkanoates
(PHAs) by Burkholderia cepacia ATCC 17759. Several inhibitory compounds present in wood hydrolysate were analyzed for effects on cell growth and PHA production
with strong inhibition observed at concentrations of 1 g/l furfural, 2 g/l vanillin, 7 g/l levulinic acid, and 1 M acetic
acid. Gradual catabolism of lower concentrations of these inhibitors was observed in this study. To increase the fermentability
of wood hydrolysate, several detoxification methods were tested. Overliming combined with low-temperature sterilization resulted
in the highest removal of total inhibitory phenolics (65%). A fed-batch fermentation exhibited maximum PHA production after
96 h (8.72 g PHA/L broth and 51.4% of dry cell weight). Compositional analysis by NMR and physical–chemical characterization
showed that PHA produced from wood hydrolysate was composed of polyhydroxybutyrate (PHB) with a molecular mass ( M
N) of 450.8 kDa, a melting temperature ( T
m) of 174.4°C, a glass transition temperature ( T
g) of 7.31°C, and a decomposition temperature ( T
decomp) of 268.6°C. 相似文献
3.
Bacterial cellulose finds novel applications in biomedical, biosensor, food, textile and other industries. The optimum fermentation
conditions for the production of cellulose by newly isolated Enterobacter amnigenus GH-1 were investigated. The strain was able to produce cellulose at temperature 25–35°C with a maximum at 28°C. Cellulose
production occurred at pH 4.0–7.0 with a maximum at 6.5. After 14 days of incubation, the strain produced 2.5 g cellulose/l
in standard medium whereas cellulose yield in the improved medium was found to be 4.1 g/l. The improved medium consisted of
4% (w/v) fructose, 0.6% (w/v) casein hydrolysate, 0.5% (w/v) yeast extract, 0.4% (w/v) disodium phosphate, and 0.115% (w/v)
citrate. Addition of metal ions like zinc, magnesium, and calcium and solvents like methanol and ethanol were found to be
stimulatory for cellulose production by the strain. The strain used natural carbon sources like molasses, starch hydrolysate,
sugar cane juice, coconut water, coconut milk, pineapple juice, orange juice, and pomegranate juice for growth and cellulose
production. Fruit juices can play important role in commercial exploitation of bacterial cellulose by lowering the cost of
the production medium. 相似文献
4.
This research was designed to maximize ethanol production from a glucose-xylose sugar mixture (simulating a sugar cane bagasse
hydrolysate) by co-fermentation with Zymomonas mobilis and Pachysolen tannophilus. The volumetric ethanol productivity of Z. mobilis with 50 g glucose/l was 2.87 g/l/h, giving an ethanol yield of 0.50 g/g glucose, which is 98% of the theoretical. P. tannophilus when cultured on 50 g xylose/l gave a volumetric ethanol productivity of 0.10 g/l/h with an ethanol yield of 0.15 g/g xylose,
which is 29% of the theoretical. On optimization of the co-fermentation with the sugar mixture (60 g glucose/l and 40 g xylose/l)
a total ethanol yield of 0.33 g/g sugar mixture, which is 65% of the theoretical yield, was obtained. The co-fermentation
increased the ethanol yield from xylose to 0.17 g/g. Glucose and xylose were completely utilized and no residual sugar was
detected in the medium at the end of the fermentation. The pH of the medium was found to be a good indicator of the fermentation
status. The optimum conditions were a temperature of 30°C, initial inoculation with Z. mobilis and incubation with no aeration, inactivation of bacterium after the utilization of glucose, followed by inoculation with
P. tannophilus and incubation with limited aeration. 相似文献
5.
Corncob acid hydrolysate, detoxed by sequently boiling, overliming and activated charcoal adsorption, was used for 2,3-butanediol production by Klebsiella oxytoca ACCC 10370. The effects of acetate in hydrolysate and pH on 2,3-butanediol production were investigated. It was found that acetic acid in hydrolysate inhibited the growth of K. oxytoca while benefited the 2,3-butanediol yield. With the increase in acetic acid concentration in medium from 0 to 4 g/l, the lag phase was prolonged and the specific growth rate decreased. The acetic acid inhibition on cell growth can be alleviated by adjusting pH to 6.3 prior to fermentation and a substrate fed-batch strategy with a low initial acetic acid concentration. Under the optimum condition, a maximal 2,3-butanediol concentration of 35.7 g/l was obtained after 60 h of fed-batch fermentation, giving a yield of 0.5 g/g reducing sugar and a productivity of 0.59 g/h l. 相似文献
6.
Succinic acid is one of the most important platform chemicals since it has great potential in industrial applications. In
this study, corncob hydrolysate was used for succinic acid production. After diluted acid treatment, xylose was released from
hemicellulose as the predominant monosaccharide in the hydrolysate, whereas glucose was released very little and most was
retained as cellulose in the raw material. Without any detoxification, corncob hydrolysate was used directly as the carbon
source in the fermentation. Actinobacillus succinogenes could utilize the sugars in the hydrolysate to produce succinic acid efficiently. Through medium optimization, yeast extract
was selected as the nitrogen source and MgCO 3 was used to control pH. A total of 23.64 g/l of succinic acid was produced with a yield of 0.58 g/g based on consumed sugar,
indicating that the waste corncob residue can be used to produce value-added chemicals practically. 相似文献
7.
The yeast Rhodotorula bogorensis produces sophorolipids of different structures to those produced by Candida bombicola. However, the yield is very low. To improve sophorolipid production by R. bogoriensis, vegetable oil was supplemented to the medium as a hydrophobic substrate: with rapeseed oil the sophorolipid yield was 1.26 g/l
but without oil was 0.33 g/l. Cultures with meadowfoam oil produced 0.77 g sophorolipids/l. Lipase-treated meadowfoam oil,
however, gave no significant increase in sophorolipid production. Possible explanations for the enhanced sophorolipid synthesis
are discussed. 相似文献
8.
In this work, corncob acid hydrolysate and its simulated medium whose sugar composition was the same as the corncob acid hydrolysate were used as fermentation substrate for lipid production by oleaginous yeast Trichosporon dermatis. On the corncob acid hydrolysate, after 7 days of fermentation, the biomass, lipid content, lipid yield, and lipid coefficient of T. dermatis were 17.3 g/L, 40.2%, 7.0 g/L, and 16.5%, respectively. Interestingly, during the lipid fermentation on the corncob acid hydrolysate, glucose, xylose, arabinose, and even acetic acid could be well utilized as carbon sources by T. dermatis. Surprisingly, the lipid yield (7.0 g/L) of T. dermatis on the corncob acid hydrolysate was much higher than that (3.8 g/L) on the simulated medium, in spite of the fact that the lipid coefficient (17.4%) on the simulated medium was a little higher. This phenomenon further showed that lignocellulosic acid hydrolysate was a suitable substrate for lipid fermentation by T. dermatis. This work would help the comprehensive utilization of lignocellulosic biomass for lipid production. 相似文献
9.
The insecticidal activity and chemical constituents of the essential oil from Ajania fruticulosa were investigated. Twelve constituents representing 91.0% of the essential oil were identified, and the main constituents were 1,8‐cineole ( 41.40% ), (+)‐camphor ( 32.10% ), and myrtenol (8.15%). The essential oil exhibited contact toxicity against Tribolium castaneum and Liposcelis bostrychophila adults with LD50 values of 105.67 μg/adult and 89.85 μg/cm 2, respectively. The essential oil also showed fumigant toxicity against two species of insect with LC50 values of 11.52 and 0.65 mg/l, respectively. 1,8‐Cineole exhibited excellent fumigant toxicity ( LC50 = 5.47 mg/l) against T. castaneum. (+)‐Camphor showed obvious fumigant toxicity ( LC50 = 0.43 mg/l) against L. bostrychophila. Myrtenol showed contact toxicity ( LD50 = 29.40 μg/cm 2) and fumigant toxicity ( LC50 = 0.50 mg/l) against L. bostrychophila. 1,8‐Cineole and (+)‐camphor showed strong insecticidal activity to some important insects, and they are main constituents of A. fruticulosa essential oil. The two compounds may be related to insecticidal activity of A. fruticulosa essential oil against T. castaneum and L. bostrychophila. 相似文献
10.
Bagasse of Agave tequilana (BAT) is the residual lignocellulosic waste that remains from tequila production. In this study we characterized the chemical
composition of BAT, which was further saccharified and fermented to produce ethanol. BAT was constituted by cellulose (42%),
hemicellulose (20%), lignin (15%), and other (23%). Saccharification of BAT was carried out at 147°C with 2% sulfuric acid
for 15 min, yielding 25.8 g/l of fermentable sugars, corresponding to 36.1% of saccharificable material (cellulose and hemicellulose
contents, w/w). The remaining lignocellulosic material was further hydrolyzed by commercial enzymes, ~8.2% of BAT load was
incubated for 72 h at 40°C rendering 41 g/l of fermentable sugars corresponding to 73.6% of the saccharificable material (w/w).
Mathematic surface response analysis of the acid and enzymatic BAT hydrolysis was used for process optimization. The results
showed a satisfactory correlation ( R
2 = 0.90) between the obtained and predicted responses. The native yeast Pichia caribbica UM-5 was used to ferment sugar liquors from both acid and enzymatic hydrolysis to ethanol yielding 50 and 87%, respectively.
The final optimized process generated 8.99 g ethanol/50 g of BAT, corresponding to an overall 56.75% of theoretical ethanol
(w/w). Thus, BAT may be employed as a lignocellulosic raw material for bioethanol production and can contribute to BAT residue
elimination from environment. 相似文献
11.
Among four cellulolytic microorganisms examined, Cellulomonas biazotea NCIM‐2550 can grow on various cellulosic substrates and produce reducing sugar. The activity of cellulases (endoglucanase, exoglucanase, and cellobiase), xylanase, amylase, and lignin class of enzymes produced by C. biazotea was mainly present extracellularly and the enzyme production was dependent on cellulosic substrates (carboxymethyl cellulose [CMC], sugarcane bagasse [SCB], and xylan) used for growth. Effects of physicochemical conditions on cellulolytic enzyme production were systematically investigated. Using MnCl 2 as a metal additive significantly induces the cellulase enzyme system, resulting in more reducing sugar production. The efficiency of fermentative conversion of the hydrolyzed SCB and xylan into clean H 2 energy was examined with seven H 2‐producing pure bacterial isolates. Only Clostridiumbutyricum CGS5 exhibited efficient H 2 production performance with the hydrolysate of SCB and xylan. The cumulative H 2 production and H 2 yield from using bagasse hydrolysate (initial reducing sugar concentration = 1.545 g/L) were approximately 72.61 mL/L and 2.13 mmol H 2/g reducing sugar (or 1.91 mmol H 2/g cellulose), respectively. Using xylan hydrolysate (initial reducing sugar concentration = 0.345 g/L) as substrate could also attain a cumulative H 2 production and H 2 yield of 87.02 mL/L and 5.03 mmol H 2/g reducing sugar (or 4.01 mmol H 2/g cellulose), respectively. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 相似文献
12.
A novel biopolyester, Medium-Chain-Length Polyhydroxyalkanoates (MCL-PHAs), was made from the corn oil hydrolysate, an inexpensive
and renewable carbon source, by a fed-batch culture of Pseudomonas putida with a phosphate limitation. The cell growth, MCL-PHAs accumulation and feeding strategies of corn oil hydrolysate in the
cultures of P. putida were investigated in 5 l and 30 l fermentors respectively. In the optimal fermentation, the final cell and MCL-PHAs concentrations
reached 103 and 28 g/l, which represents a MCL-PHAs productivity of 0.61 g/l h. It was confirmed by its NMR spectrum that
this MCL-PHAs from corn oil hydrolysate contained 4 saturated and 3 unsaturated monomers with a chain length of 6–14 carbon
atoms. 相似文献
13.
Spore-forming Bacillus sp. has been extensively studied for their probiotic properties. In this study, an acid-treated rice straw hydrolysate was used as carbon source to produce the spores of Bacillus coagulans. The results showed that this hydrolysate significantly improved the spore yield compared with other carbon sources such as glucose. Three significant medium components including rice straw hydrolysate, MnSO 4 and yeast extract were screened by Plackett–Burman design. These significant variables were further optimized by response surface methodology (RSM). The optimal values of the medium components were rice straw hydolysate of 27% (v/v), MnSO 4 of 0·78 g l −1 and yeast extract of 1·2 g l −1. The optimized medium and RSM model for spore production were validated in a 5 l bioreactor. Overall, this sporulation medium containing acid-treated rice straw hydrolysate has a potential to be used in the production of B. coagulans spores. 相似文献
14.
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 H 2SO 4. 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
15.
Corncob is a potential feedstock in Thailand that can be used for fermentable sugar production through dilute sulfuric acid pretreatment and enzymatic hydrolysis. To recover high amounts of monomeric sugars from corncob, the sulfuric pretreatment conditions were optimized by using response surface methodology with three independent variables: sulfuric acid concentration, temperature, and time. The highest response of total sugars, 48.84 g/L, was found at 122.78°C, 4.65 min, and 2.82% (v/v) H 2SO 4. With these conditions, total sugars from the confirmation experiment were 46.29 g/L, with 5.51% error from the predicted value. The hydrolysate was used as a substrate for acetone–butanol–ethanol fermentation to evaluate its potential for microbial growth. The simultaneous saccharification and fermentation (SSF) showed that C. beijerinckii TISTR 1461 can generate acetone–butanol–ethanol products at 11.64 g/L (5.29 g/L acetone, 6.26 g/L butanol, and 0.09 g/L ethanol) instantly using sugars from the hydrolysed corncob with Novozymes 50013 cellulase enzyme without an overliming process. 相似文献
16.
In a microbial electrolysis cell (MEC), hydrolysate produced by hydrothermal treatment of wheat straw was used for hydrogen
production during selective recovery of phenols. The average H 2 production rate was 0.61 m 3 H 2/m 3 MEC·day and equivalent to a rate of 0.40 kg COD/m 3 MEC·day. The microbial community in the anode biofilm was adapted by establishment of xylose-degrading bacteria of the Bacteriodetes
phylum (16%) and Geobacter sulfurreducens (49%). During the process, 61% of the chemical oxygen demand was removed as hydrogen at 64% yield. The total energy production
yield was 78% considering the energy content in the consumed compounds and the cell voltage of 0.7 V. The highest hydrogen
production was equivalent to 0.8 kg COD/m 3 MEC·day and was obtained at pH 7–8 and 25°C. Accumulation of 53% w/v phenolic compounds in the liquor was obtained by stepwise
addition of the hydrolysate during simultaneous production of hydrogen from consumption of 95% for the hemicellulose and 100%
of the fatty acids. Final calculations showed that hydrolysate produced from 1 kg wheat straw was upgraded by means of the
MEC to 22 g hydrogen (266 L), 8 g xylan, and 9 g polyphenolics for potential utilization in biobased materials. 相似文献
17.
Microalgal lipids are the oils of future for sustainable biodiesel production. However, relatively high production costs due
to low lipid productivity have been one of the major obstacles impeding their commercial production. We studied the effects
of nitrogen sources and their concentrations on cell growth and lipid accumulation of Neochloris oleoabundans, one of the most promising oil-rich microalgal species. While the highest lipid cell content of 0.40 g/g was obtained at
the lowest sodium nitrate concentration (3 mM), a remarkable lipid productivity of 0.133 g l −1 day −1 was achieved at 5 mM with a lipid cell content of 0.34 g/g and a biomass productivity of 0.40 g l −1 day −1. The highest biomass productivity was obtained at 10 mM sodium nitrate, with a biomass concentration of 3.2 g/l and a biomass
productivity of 0.63 g l −1 day −1. It was observed that cell growth continued after the exhaustion of external nitrogen pool, hypothetically supported by the
consumption of intracellular nitrogen pools such as chlorophyll molecules. The relationship among nitrate depletion, cell
growth, lipid cell content, and cell chlorophyll content are discussed. 相似文献
18.
This study examined the pretreatment, enzymatic saccharification, and fermentation of the red macroalgae Gracilaria verrucosa using adapted saccharomyces cerevisiae to galactose or NaCl for the increase of bioethanol yield. Pretreatment with thermal acid hydrolysis to obtain galactose was carried out with 11.7% (w/v) seaweed slurry and 373 mM H2SO4 at 121 °C for 59 min. Glucose was obtained from enzymatic hydrolysis. Enzymatic saccharification was performed with a mixture of 16 U/mL Celluclast 1.5L and Viscozyme L at 45 °C for 48 h. Ethanol fermentation in 11.7% (w/v) seaweed hydrolysate was carried out using Saccharomyces cerevisiae KCTC 1126 adapted or non-adapted to high concentrations of galactose or NaCl. When non-adapted S. cerevisiae KCTC 1126 was used, the ethanol productivity was 0.09 g/(Lh) with an ethanol yield of 0.25. Ethanol productivity of 0.16 and 0.19 g/(Lh) with ethanol yields of 0.43 and 0.48 was obtained using S. cerevisiae KCTC 1126 adapted to high concentrations of galactose and NaCl, respectively. Adaptation of S. cerevisiae KCTC 1126 to galactose or NaCl increased the ethanol yield via adaptive evolution of the yeast. 相似文献
19.
In this study, the yeast strain P10 which was identified to be a member of Aureobasidium pullulans var. melanogenum isolated from the mangrove ecosystems was found to be able to accumulate high content of oil in its cells. After optimization of the medium for lipid production and cell growth by the yeast strain P10, it was found that 8.0 g of glucose per 100 ml, 0.02 g of yeast extract per 100 ml, 0.02 g of ammonium sulfate per 100 ml, pH 6.0 in the medium were the most suitable for lipid production. During 10-l fermentation, a titer was 66.3 g oil per 100 g of cell dry weight, cell mass was 1.3 g per 100 ml, a yield was 0.11 g of oil per g of consumed sugar and a productivity was 0.0009 g of oil per g of consumed sugar per h within 120 h. At the same time, only 0.07 g of reducing sugar per 100 ml was left in the fermented medium. The compositions of the fatty acids produced were C 16:0 (26.7%), C 16:1(1.7%), C 18:0 (6.1%), C 18:1 (44.5%), and C 18:2 (21.0%). The biodiesel produced from the extracted lipid could be burnt well. 相似文献
20.
A brewery spent-grain hemicellulosic hydrolysate was used for xylitol production by Debaryomyces hansenii. Addition of 6 g yeast extract/l increased the xylitol yield to 0.57 g/g, and productivity to 0.51 g/l h that were, respectively,
1.4 -and 1.8-times higher than the values obtained with non-supplemented hydrolysate. When corn steep liquor was combined
with 3 g yeast extract/l, the highest xylitol yield, 0.58 g/g, was obtained with a similar productivity. 相似文献
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