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1.
The production of fermentable sugars from rice hull was studied by dilute acid pretreatment and enzymatic saccharification.
Rice hull (15%, w/ v) was pretreated by 1% ( v/ v) sulfuric acid at high temperature (120∼160 °C) for 15, 30, 45, and 60 min, respectively. The maximum sugar concentration
from rice hull in the prehydrolysate was obtained at 140 °C for 30 min, but the enzymatic saccharification yield from the
corresponding pretreated rice hull is not high. To another aspect, the maximum enzymatic saccharification yield was achieved
at 160 °C for 60 min, while the recovery of fermentable sugars was the poorest. To take account of fermentable sugars from
pretreatment and enzymatic saccharification, the maximum yield of sugars was obtained only when rice hull was treated at 140 °C
for 30 min. Under this condition, 72.5% ( w/ w) of all sugars generated from the raw material can be recovered. The kinetic study on the enzymatic saccharification of dilute
acid pretreated rice hull was also performed in this work by a modified Michaelis–Menten model and a diffusion-limited model.
After calculation by a linear and a non-linear regression analysis, both models showed good relation with the experimental
results. 相似文献
2.
There is a lack of fundamental knowledge about the scale up of biosurfactant production. In order to develop suitable technology
of commercialization, carrying out tests in shake flasks and bioreactors was essential. A reactor with integrated foam collector
was designed for biosurfactant production using Bacillus subtilis isolated from agricultural soil. The yield of biosurfactant on biomass ( Y
p/x), biosurfactant on sucrose ( Y
p/s), and the volumetric production rate ( Y) for shake flask were obtained about 0.45 g g −1, 0.18 g g −1, and 0.03 g l −1 h −1, respectively. The best condition for bioreactor was 300 rpm and 1.5 vvm, giving Y
x/s, Y
p/x, Y
p/s, and Y of 0.42 g g −1, 0.595 g g −1, 0.25 g g −1, and 0.057 g l −1 h −1, respectively. The biosurfactant maximum production, 2.5 g l −1, was reached in 44 h of growth, which was 28% better than the shake flask. The obtained volumetric oxygen transfer coefficient
( K
L
a) values at optimum conditions in the shake flask and the bioreactor were found to be around 0.01 and 0.0117 s −1, respectively. Comparison of K
L
a values at optimum conditions shows that biosurfactant production scaling up from shake flask to bioreactor can be done with
K
L
a as scale up criterion very accurately. Nearly 8% of original oil in place was recovered using this biosurfactant after water
flooding in the sand pack. 相似文献
3.
Biosurfactants are of considerable interest due to their biodegradability, low degree of toxicity, and diverse applications. However, the high production costs involved in the acquisition of biosurfactants underscore the need for optimization of the production process to enable viable application on an industrial scale. The aims of the present study were to select a species of Candida that produces a biosurfactant with the greatest emulsifying potential and to investigate the influence of components of the production medium and cultivation conditions. Candida utilis achieved the lowest surface tension (35.53 mN/m), best emulsification index (73 %), and highest yield (12.52 g/l) in a medium containing waste canola frying oil as the carbon source and ammonium nitrate as the nitrogen source. The best combination of medium components and cultivation conditions was 6 % ( w/ v) glucose, 6 % ( w/ v) waste canola frying oil, 0.2 % ( w/ v) ammonium nitrate, 0.3 % ( w/ v) yeast extract, 150 rpm, 1 % inoculum ( w/ v), and 88 h of fermentation. The greatest biosurfactant production and the lowest surface tension were achieved in the first 24 h of production, and the maximum biomass production was recorded at 72 h. The biosurfactant produced from C. utilis under the conditions investigated in the present study has a potential to be a bioemulsifier for application in the food industry. 相似文献
4.
Plasma-assisted pretreated wheat straw was investigated for cellulase and xylanase production by Trichoderma reesei fermentation. Fermentations were conducted with media containing washed and unwashed plasma-assisted pretreated wheat straw
as carbon source which was sterilized by autoclavation. To account for any effects of autoclavation, a comparison was made
with unsterilized media containing antibiotics. It was found that unsterilized washed plasma-assisted pretreated wheat straw
(which contained antibiotics) was best suited for the production of xylanases (110 IU ml −1) and cellulases (0.5 filter paper units (FPU) ml −1). Addition of Avicel boosted enzyme titers with the highest cellulase titers (1.5 FPU ml −1) found with addition of 50 % w/ w Avicel and with the highest xylanase production (350 IU ml −1) reached in the presence of 10 % w/ w Avicel. Comparison with enzyme titers from other nonrefined feedstocks suggests that plasma pretreated wheat straw is a promising
and suitable substrate for cellulase and hemicellulase production. 相似文献
5.
An actinomycete strain, isolated from a soil sample under a sugar cane plantation in Brazil and identified as Streptomyces viridobrunneus SCPE-09, was selected as a promising cellulolytic strain, and tested for its ability to produce cellulases from agro-industrial
residues. Sugar cane bagasse or wheat bran was tested as carbon source, and corn steep liquor tested as nitrogen source. Different
concentrations of carbon and nitrogen were tested using factorial design to identify optimal cellulose production. The results
showed that media containing wheat bran 2.0% ( w/ v) and corn steep liquid 0.19% ( w/ v) lead to the highest production, 2.0 U mL −1 of CMCase, obtained on the fifth day of fermentation. The pH and temperature profile showed optimal activity at pH 4.9 and
50°C. As for thermostability, endoglucanases were most tolerant at 50°C, retaining more than 80% of maximal activity even
after 2 h of incubation. Zymogram analyses using supernatant from growth under optimized conditions revealed the presence
of two CMCase bands with apparent molecular masses of 37 and 119 kDa. The combination of pH tolerance and CMCase production
from agro-industrial residues by S. viridobrunneus SCPE-09 offers promise for future bioethanol biotechnologies. 相似文献
6.
Pseudomonas aeruginosa strain OBP1, isolated from petroleum sludge, was used to produce biosurfactant from a modified mineral salt medium with 2%
n-hexadecane as sole source of carbon. The crude biosurfactant was fractionated using TLC and HPLC. Using FTIR spectroscopy,
1H NMR, and LC-MS analyses, the chemical structure of the purified fraction of crude biosurfactant was identified as rhamnolipid
species. The LC-MS spectra show that monorhamnolipid ( l-rhamnopyranosyl-β-hydroxydecanoyl-β- hydroxydecanoate, Rha-C 10-C 10) was produced in abundance with the predominant congener [M–H] − ions for l-rhamnopyranosyl- l-rhamnopyranosyl-3-hydroxydecanoyl-3-hydroxydecanoate (Rha-Rha-C 10-C 10). Seven different carbon substrates and five nitrogen sources were examined for their effect on rhamnolipid production. Using
n-hexadecane (20 g/l) as carbon substrate and urea along with (NH 4) 2SO 4 (2 g/l each) as nitrogen source was found to be the best, with a maximum yield of 4.8 g/l. The biosurfactant reduced the
surface tension of water to 31.1 mNm −1 with a critical micelle concentration of 45 mg/l. The biosurfactant showed a better emulsifying activity against a variety
of hydrocarbon and achieved a maximum emulsion index of 82% for diesel. The purified biosurfactant showed a significant antibacterial
activity against Staphylococcus aureus at a minimum inhibitory concentration of 8 μg/ml. 相似文献
7.
The thermostable and organic solvent tolerant whole-cell lipase (WCL) was produced by Burkholderia sp. ZYB002 with broad spectrum organic solvent tolerance. The production medium of the WCL was primarily optimized, which
resulted in the maximum activity of 22.8 U/mL and the 5.1-fold increase of the WCL yield. The optimized culture medium was
as follows (% w/v or v/v): soybean meal 2, soybean oil 0.5, manganese sulfate 0.1, K 2HPO 4 0.1, olive oil 0.5, initial pH 6.0, inoculum density 2, liquid volume 35 mL in 250-mL Erlenmeyer flask, and incubation time
24 h. The biochemical characterization of the WCL from Burkholderia sp. ZYB002 was determined, and the results showed that the optimal pH and temperature for lipolytic activity of the WCL was
8.0 and 65°C, respectively. The WCL was stable at temperature up to 70°C for 1 h and retained 79.2% of its original activity.
The WCL was highly stable in the pH range from 3.0 to 8.5 for 6 h. Ca 2+, K +, Na +, NO 3−, etc. ions stimulated its lipolytic activity, whereas Zn 2+ ion caused inhibition effect. The WCL was also relatively stable in n-butanol at a final concentration of 50% ( v/v) for 24 h. However, the WCL was strongly inhibited in Triton X-100 at a final concentration of 10% ( v/v). The WCL with thermal resistance and organic solvent tolerance showed its great potential in various green industrial chemical
processes. 相似文献
8.
There is an increasing interest for the organic residues from various sectors of agriculture and industries over the past
few decades. Their application in the field of fermentation technology has resulted in the production of bulk chemicals and
value-added products such as amino acid, enzymes, mushroom, organic acids, single-cell protein, biologically active secondary
metabolites, etc. (Ramachandran et al., Bioresource Technology 98:2000–2009, 2007). In this work, the production of extracellular xylanase by the fungus Penicillium canescens was investigated in solid-state fermentation using five agro-industrial substrates (soya oil cake, soya meal, wheat bran,
whole wheat bran, and pulp beet). The best substrate was the soya oil cake. In order to optimize the production, the most
effective cultivation conditions were investigated in Erlenmeyer flasks and in plastic bags with 5 and 100 g of soya oil cake,
respectively. The initial moisture content, initial pH, and temperature of the culture affected the xylanase synthesis. The
optimal fermentation medium was composed by soya oil cake crushed to 5 mm supplemented with 3% and 4% ( w/ w) of casein peptone and Na 2HPO 4.2H 2O. After 7 days of incubation at 30 °C and under 80% of initial moisture, a xylanase production level of 18,895 ± 778 U/g
(Erlenmeyer flasks) and 9,300 ± 589 U/g (plastic bags) was reached. The partially purified enzyme recovered by ammonium sulfate
fractionation was completely stable at freezing and refrigeration temperatures up to 6 months and reasonably stable at room
temperature for more than 3 months. 相似文献
9.
A cloud-point extraction (CPE) method using Triton X-114 non-ionic surfactant was developed for the extraction and preconcentration
of carbamate insecticide residues (i.e., methomyl, propoxur, carbofuran, carbaryl, isoprocarb, and promecarb) in fruit samples.
The optimum conditions of CPE were 1.5% ( w/ v) Triton X-114, 7.0% ( w/ v) NaCl and 20 min equilibrated at 45 °C. The surfactant-rich phase was then analyzed by reversed-phase high-performance liquid
chromatography with ultraviolet detection at 270 nm, under gradient separation using methanol and 0.1% ( v/ v) acetic acid. Under the study conditions, six carbamate insecticides were successfully separated within 27 min. Good reproducibility
was obtained with the relative standard deviation of <3% for retention time and <9% for peak area. Limits of detection in
the studied fruit samples were in the range of 0.1–1.0 mg kg −1. No carbamate insecticides were detected in the studied fruit samples. The high recoveries of the spiked fruit samples were
obtained in the range 80.0–107%. The CPE method has been shown to be a potential useful methodology for the preconcentration
of the target analytes, with a preconcentration factor of 14. Moreover, the method is simple, has high sensitivity, consumes
much less solvent than traditional methods, and is environmental friendly. 相似文献
10.
Alkaline proteases from the viscera of the striped seabream ( Lithognathus mormyrus) were extracted and characterized. Interestingly, the crude enzyme was active over a wide range of pH from 6.0 to 11.0, with
an optimum pH at the range of 8.0–10.0. In addition, the crude protease was stable over a broad pH range (5.0–12.0). The optimum
temperature for enzyme activity was 50 °C. The crude alkaline proteases showed stability towards various surfactants and bleach
agents and compatibility with some commercial detergents. It was stable towards several organic solvents and retained more
than 50% of its original activity after 30 days of incubation at 30 °C in the presence of 25% ( v/ v) dimethyl sulfoxide, N, N-dimethylformamide, diethyl ether, and hexane. The crude enzyme extract was also tested for shrimp waste deproteinization
in the preparation of chitin. The protein removal with a ratio enzyme/substrate of 10 was about 79%. 相似文献
11.
The enzyme β- d-fructofuranosidase fructohydrolase (FFH) cleaves the α-1,4 glycosidic linkage between α- d-glucose and β- d-fructose molecules of sucrose, releasing monosaccharides by hydrolysis. In the present study, FFH production in Candida utilis GC-46, a lipolytic wild yeast strain was improved by exposure to N-methyl N-nitro N-nitroso guanidine (NG) and 2-deoxy- d-glucose (2dg) at various levels. The mutant strain NG-5 was obtained after exposure to 0.06 mg/ml of NG for 20 min. NG-5
offers improved extracellular FFH production (34 ± 2.6 U/ml/min) when compared to the wild strain (1.15 ± 0.01 U/ml/min).
A 40-fold increase of FFH (45.65 ± 2.0 U/ml/min) was achieved when the process parameters, including incubation period (48 h),
sucrose concentration (5.0 g/l), initial pH (6.0), inoculum size (2.0% v/ v, 16 h old), and urea concentration (0.2%, w/ v) were identified using Plackett–Burman design. The kinetic parameters viz. Q
p (0.723 U/g/h), Y
p/s (2.036 U/g), and q
p (0.091 U/g yeast cells/h) indicate that NG-5 is a hyperproducer of extracellular FFH with a concomitant increase in growth
rate. The volumetric productivity of NG-5 was over sixfold improved over the parental strain. The enzyme production improvement
is highly significant (HS, LSD 0.042, p ≤ 0.05), indicating commercial utility. 相似文献
12.
This paper reports an investigation of the effects of solvent system, solution concentration, and applied electrostatic field
strength (EFS) on the morphological appearance and/or size of as-spun cellulose acetate (CA) products. The single-solvent
systems were acetone, chloroform, N, N
-dimethylformamide (DMF), dichloromethane (DCM), methanol (MeOH), formic acid, and pyridine. The mixed-solvent systems were
acetone–DMAc, chloroform–MeOH, and DCM–MeOH. Chloroform, DMF, DCM, MeOH, formic acid, and pyridine were able to dissolve CA,
forming clear solutions (at 5% w/ v), but electrospinning of these solutions produced mainly discrete beads. In contrast, electrospinning of the solution of
CA in acetone produced short and beaded fibers. At the same solution concentration of 5% ( w/ v) electrospinning of the CA solutions was improved by addition of MeOH to either chloroform or DCM. For all the solvent systems
investigated smooth fibers were obtained from 16% ( w/ v) CA solutions in 1:1, 2:1, and 3:1 ( v/ v) acetone–DMAc, 14–20% ( w/ v) CA solutions in 2:1 ( v/ v) acetone–DMAc, and 8–12% ( w/ v) CA solutions in 4:1 ( v/ v) DCM–MeOH. For the as-spun fibers from CA solutions in acetone–DMAc the average diameter ranged between 0.14 and 0.37 μm
whereas for the fibers from solutions in DCM–MeOH it ranged between 0.48 and 1.58 μm. After submersion in distilled water
for 24 h the as-spun CA fibers swelled appreciably (i.e. from 620 to 1110%) but the physical integrity of the fibrous structure
remained intact. 相似文献
13.
Among all endophytic keratinolytic fungal isolates recovered from marine soft coral Dendronephthya hemprichii, Penicillium spp. Morsy1 was selected as the hyperactive keratinolytic strain under solid substrate fermentation of different agriculture
and poultry wastes. The optimization of extraction process, physicochemical parameters affecting the keratinase production
in solid-state fermentation, and the purified keratinase parameters were studied. Maximum keratinase activity (1,600 U g −1, initial dry substrate) was recovered from moldy bran with 0.1% Tween 80. The optimized production conditions were rice straw
as carbon source, pH of medium 6, growth temperature 26 °C, initial moisture content of 80% ( v/ w), inoculum size of 10 5 spores ml −1, and an average particle size of the substrate 0.6 mm (3,560 U g −1, initial dry substrate after 5 days of fermentation). Two types of keratinase (Ahm1 and Ahm2) were purified from the culture
supernatant through ammonium sulfate precipitation, DEAE-Sepharose, and gel filtration chromatography. Enzyme molecular weights
were 19 kDa (Ahm1) and 40 kDa (Ahm2). The kinetic parameters of purified keratinases were optimized for the hydrolysis of
azokeratin by Ahm1 (pH 7.0–8.0, stable in pH range of 6.0 to 8.0 at 50 °C) and Ahm2 enzymes (pH 10.0–11.0, stable in pH range
of 6.0 to 11.0 at 60–65 °C). Whereas inhibitors of serine (phenylmethylsulfonyl fluoride) and cysteine (iodoacetamide) proteases
had minor effects on both Ahm1 and Ahm2 activity, both keratinases were strongly inhibited by chelating agents EDTA and EGTA.
These findings suggest that serine and cysteine residues are not involved in the catalytic mechanisms, and they are metalloproteases. 相似文献
14.
A salt-tolerant bacterium was isolated from the surface soil of a pharmaceutical factory, which could efficiently decolorize
azo dyes. The strain was identified as Exiguobacterium sp. according to its morphological characteristics and 16S rRNA gene sequence analysis. Decolorization of X-3B with resting
cells of this strain, which were catalyzed by redox mediator (anthraquinone), was studied, and the conditions were optimized.
For color removal and cells growth, the optimal inoculation amount, pH, temperature, salinity, and metal ions were 6% ( v/ v), 5.4–7.0, 30–40 °C, 15% ( w/ v) NaCl, and 1 mmol L −1 Mg 2+ or Ca 2+, respectively. It was exhibited that decolorization process proceeded primarily by enzymatic reduction associated with a
minor portion of bio-adsorption to inactivated microbial cells. Anthraquinone could really accelerate the decolorization of
X-3B under the optimal conditions. 相似文献
15.
In this work, the potential of microwave-assisted alkali pretreatment in order to improve the rupture of the recalcitrant
structures of the cashew able bagasse (CAB), lignocellulosic by-product in Brazil with no commercial value, is obtained from
cashew apple process to juice production, was studied. First, biomass composition of CAB was determined, and the percentage
of glucan and lignin was 20.54 ± 0.70% and 33.80 ± 1.30%, respectively. CAB content in terms of cellulose, hemicelluloses,
and lignin, 19.21 ± 0.35%, 12.05 ± 0.37%, and 38.11 ± 0.08%, respectively, was also determined. Results showed that, after
enzymatic hydrolysis, alkali concentration exerted influence on glucose formation, after pretreatment with 0.2 and 1.0 mo L −1 of NaOH (372 ± 12 and 355 ± 37 mg g glucan−1) when 2% ( w/ v) of cashew apple bagasse pretreated by microwave-assisted alkali pretreatment (CAB-M) was used. On the other hand, pretreatment
time (15–30 min) and microwave power (600–900 W) exerted no significant effect on hydrolysis. On enzymatic hydrolysis step,
improvement on solid percentage (16% w/ v) and enzyme load (30 FPU g CAB-M−1) increased glucose concentration to 15 g L −1. The fermentation of the hydrolyzate by Saccharomyces cerevesiae resulted in ethanol concentration and productivity of 5.6 g L −1 and 1.41 g L −1 h −1, respectively. 相似文献
16.
The modified medium composed of the alkaline-pretreated oil palm empty fruit bunch (APEFB) and tuna condensate powder was used for cellulase and xylanase productions by Streptomyces thermocoprophilus strain TC13W. The APEFB contained 74.46% (w/w) cellulose, 15.72% (w/w) hemicellulose, and 6.40% (w/w) lignin. The tuna condensate powder contained 55.49% (w/w) protein and 11.05% (w/w) salt. In the modified medium with only 6.75 g/l tuna condensate powder, 10 g/l APEFB, and 0.5 g/l Tween 80, S. thermocoprophilus strain TC13W produced cellulase 4.9 U/ml and xylanase 9.0 U/ml. The enzyme productions in the modified medium were lower than cellulase (6.0 U/ml) and xylanase (12.0 U/ml) productions in the complex medium (CaCl2 0.1, MgSO4·7H2O 0.1, KH2PO4 0.5, K2HPO4 1.0, NaCl 0.2, yeast extract 5.0, NH4NO3 1.0, Tween 80 0.5). When tuna condensate powder in the modified medium was reduced to 5.0 g/l and Tween 80 was increased to 1.5 g/l, S. thermocoprophilus strain TC13W produced cellulase and xylanase activities of 9.1 and 12.1 U/ml, respectively. This study shows that the cost of enzyme production could be reduced by using pretreated EFB and tuna condensate as a carbon and a nitrogen source, respectively. 相似文献
17.
Pseudomonas aeruginosa PACL strain, isolated from oil-contaminated soil taken from a lagoon, was used to investigate the efficiency and magnitude
of biosurfactant production, using different waste frying soybean oils, by submerged fermentation in stirred tank reactors
of 6 and 10 l capacities. A complete factorial experimental design was used, with the goal of optimizing the aeration rate
(0.5, 1.0, and 1.5 vvm) and agitation speed (300, 550, and 800 rpm). Aeration was identified as the primary variable affecting
the process, with a maximum rhamnose concentration occurring at an aeration rate of 0.5 vvm. At optimum levels, a maximum
rhamnose concentration of 3.3 g/l, an emulsification index of 100%, and a minimum surface tension of 26.0 dynes/cm were achieved.
Under these conditions, the biosurfactant production derived from using a mixture of waste frying soybean oil (WFSO) as a
carbon source was compared to production when non-used soybean oil (NUSO), or waste soybean oils used to fry specific foods,
were used. NUSO produced the highest level of rhamnolipids, although the waste soybean oils also resulted in biosurfactant
production of 75–90% of the maximum value. Under ideal conditions, the kinetic behavior and the modeling of the rhamnose production,
nutrient consumption, and cellular growth were established. The resulting model predicted data points that corresponded well
to the empirical information. 相似文献
18.
The production of biosurfactant, a surface-active compound, by two Serratia marcescens strains was tested on minimal culture medium supplemented with vegetable oils, considering that it is well known that these
compounds stimulate biosurfactant production. The vegetable oils tested included soybean, olive, castor, sunflower, and coconut
fat. The results showed a decrease in surface tension of the culture medium without oil from 64.54 to 29.57, with a critical
micelle dilution (CMD −1) and CMD −2 of 41.77 and 68.92 mN/m, respectively. Sunflower oil gave the best results (29.75 mN/m) with a CMD −1 and CMD −2 of 36.69 and 51.41 mN/m, respectively. Sunflower oil contains about 60% of linoleic acid. The addition of linoleic acid decreased
the surface tension from 53.70 to 28.39, with a CMD −1 of 29.72 and CMD −2 of 37.97, suggesting that this fatty acid stimulates the biosurfactant production by the LB006 strain. In addition, the crude
precipitate surfactant reduced the surface tension of water from 72.00 to 28.70 mN/m. These results suggest that the sunflower
oil’s linoleic acid was responsible for the increase in biosurfactant production by the LB006 strain. 相似文献
19.
In our previous study, chitosan–alginate microcapsules were developed to protect egg yolk immunoglobulin (IgY) from gastric
inactivation. The present study was undertaken to determine the effect of chitosan concentration (0–0.8%; w/ v) on various properties of the microcapsules in order to produce the optimum chitosan–alginate microcapsules for use in the
oral delivery of IgY. The properties investigated included microcapsule morphology, loading capacity for IgY (expressed as
the IgY loading percentage, w/ w, of microcapsules), encapsulation efficiency (EE%), in vitro gastroresistance, and IgY release. IgY loading percentage and
EE% were both highest at 0.2% ( w/ v) chitosan, and, above this level, further increases were not observed. The stability of IgY in simulated gastric fluid (pH
1.2) was significantly improved by encapsulation in alginate microcapsules (IgY retained 43.5% of its activity) and was further
improved by including chitosan at any of the chitosan concentrations assessed (IgY retained an average of 69.4% activity)
although there was no difference in protection of gastric inactivation among concentrations of chitosan varying from 0.05%
to 0.8% ( w/ v). Higher chitosan concentrations (i.e., ≥0.2%; w/ v) prolonged the release of IgY from the microcapsules during simulated intestinal fluid incubation (pH 6.8). However, above
the 0.2% ( w/ v) level, no significant differences were observed. We conclude that the optimum chitosan concentration for microencapsulation
is 0.2% ( w/ v). 相似文献
20.
In this study, biosurfactant-producing bacteria was evaluated for biosurfactant production by using banana peel as a sole carbon source. From the 71 strains screened, Halobacteriaceae archaeon AS65 produced the highest biosurfactant activity. The highest biosurfactant production (5.30 g/l) was obtained when the cells were grown on a minimal salt medium containing 35 % ( w/ v) banana peel and 1 g/l commercial monosodium glutamate at 30 °C and 200 rpm after 54 h of cultivation. The biosurfactant obtained by extraction with ethyl acetate showed high surface tension reduction (25.5 mN/m), a small critical micelle concentration value (10 mg/l), thermal and pH stability with respect to surface tension reduction and emulsification activity, and a high level of salt tolerance. The biosurfactant obtained was confirmed as a lipopeptide by using a biochemical test FT-IR, NMR, and mass spectrometry. The crude biosurfactant showed a broad spectrum of antimicrobial activity and had the ability to emulsify oil, enhance PAHs solubility, and oil bioremediation. 相似文献
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