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1.
Microbial-derived surfactants are molecules of great interest due to their environmentally friendly nature and low toxicity; however, their production cost is not competitive when compared to synthetics. Marine microorganisms are exposed to extremes of pressure, temperature, and salinity; hence, they can produce stable compounds under such conditions that are useful for industrial applications. A screening program to select marine bacteria able to produce biosurfactant using low-cost substrates (mineral oil, sucrose, soybean oil, and glycerol) was conducted. The selected bacterial strain showed potential to synthesize biosurfactants using mineral oil as carbon source and was identified as Brevibacterium luteolum. The surface-active compound reduced the surface tension of water to 27 mN m?1 and the interfacial tension (water/hexadecane) to 0.84 mN m?1 and showed a critical micelle concentration of 40 mg L?1. The biosurfactant was stable over a range of temperature, pH, and salt concentration and the emulsification index (E24) with different hydrocarbons ranging from 60 to 79 %. Structural characterization revealed that the biosurfactant has a lipopeptide nature. Sand washing removed 83 % of crude oil demonstrating the potential of the biosurfactants (BS) for bioremediation purposes. The new marine B. luteolum strain showed potential to produce high surface-active and stable molecule using a low-cost substrate.  相似文献   

2.
The metabolism of residual glycerol from biodiesel synthesis by Klebsiella pneumoniae BLh-1 was investigated in this study. Batch and fed-batch cultivations were performed in bioreactors under anaerobic and oxygen limitation conditions. Results of batch cultivations showed that the main product was 1,3-propanediol (1,3-PD) in both conditions, although the higher yields and productivities (0.46 mol mol?1 glycerol and 1.22 g?L?1?h?1, respectively) were obtained under anaerobic condition. Large amounts of ethanol were also produced under batch anaerobic condition, peaking at 12.30 g?L?1. Batch cultivations under oxygen limitation were characterized by faster growth kinetics, with higher biomass production but lower conversions of glycerol into 1,3-PD, with yields and productivities of 0.33 mol mol?1 glycerol and 0.99 g?L?1?h?1, respectively. The fed-batch cultivations were carried out in order to investigate the effects of feeding of raw glycerol on cells. Fed-batch under anaerobiosis showed that 1,3-PD and ethanol concentrations increased with the feeding rate, with maximal productions of 26.12 and 19.2 g?L?1, respectively. The oxygen limitation conditions diverted the bacterium metabolism to an elevated lactic acid formation, reaching 59 g?L?1 in higher feeding rates of glycerol, but lowering the production of ethanol.  相似文献   

3.
The production of biosurfactant by Bacillus subtilis ATCC 6633 was investigated using commercial sugar, sugarcane juice and cane molasses, sugarcane juice alcohol stillage, glycerol, mannitol, and soybean oil. Commercial sugar generated the minimum values of surface tension, with the best results (28.7 mN/m, (relative critical micelle concentration [CMC−1] of 78.6) being achieved with 10 g of substrate/L in 48 h. At a pH between 7.0 and 8.0, a higher production of surface-active compounds and a greater emulsifier activity was also observed. Enrichment of the culture medium with trace minerals and EDTA showed maximum yields, whereas supplementation with yeast extract stimulated only cell growth. The kinetic studies revealed that biosurfactant production is a cell growth-associated process; surface tension, CMC, and emulsification index values of 29.6 dyn/cm, 82.3, and 57%, respectively, were achieved, thus indicating that it is feasible to produce biosurfactants from a renewable and low-cost carbon source.  相似文献   

4.
Bacillus subtilis LAMI008 strain isolated from the tank of Chlorination at the Wastewater Treatment Plant on Campus do Pici in Federal University of Ceará, Brazil has been screened for surfactin production in mineral medium containing clarified cashew apple juice (MM-CAJC). Results were compared with the ones obtained using mineral medium with glucose PA as carbon source. The influence on growth and surfactin production of culture medium supplementation with yeast extract was also studied. The substrate concentration analysis indicated that B. subtilis LAMI008 was able to degrade all carbon sources studied and produce biosurfactant. The highest reduction in surface tension was achieved with the fermentation of MM-CAJC, supplemented with yeast extract, which decreased from 58.95?±?0.10 to 38.10?±?0.81 dyn cm?1. The biosurfactant produced was capable of emulsifying kerosene, achieving an emulsification index of 65%. Surfactin concentration of 3.5 mg L?1 was obtained when MM-CAJC, supplemented with yeast extract, was used, thus indicating that it is feasible to produce surfactin from clarified cashew apple juice, a renewable and low-cost carbon source.  相似文献   

5.
Biosurfactant produced by Pseudomonas aeruginosa, Bacillus subtilis and Rhodococcus erythropolis that isolated from the formation water of Chinese petroleum reservoir has been compared in surface abilities and oil recovery. Maximum biosurfactant production reached to about 2.66 g/l and the surface tension of liquid decreased from 71.2 to 22.56 mN/m using P. aeruginosa. Three strains exhibited a good ability to emulsify the crude oil, and biosurfactant of P. aeruginosa attained an emulsion index of 80% for crude oil which was greater than other strains. Stability studies were carried out under the extreme environmental conditions, such as high temperature, pH, salinity and metal ions. Results showed an excellent resistance of all biosurfactants to retain their surface-active properties at extreme conditions. It was found that the biosurfactants from three isolated bacteria showed a good stability above pH of 5, but at lower pH (from 1 to 5) they will harmfully be affected. They were able to support the condition up to 20 g/l salinity. P. aeruginosa biosurfactant was even stable at the higher salinity. Regarding temperature, all produced biosurfactants demonstrated a good stability in the temperature up to 120 °C. But stability of three biosurfactants was affected by monovalent and trivalent ions. Oil recovery experiments in physical simulation showed 7.2-14.3% recovery of residual oil after water flooding when the biosurfactant of three strains was added. These results suggest that biosurfactants of these indigenous isolated strains are appropriate candidates for enhanced oil recovery with a preference to biosurfactant of P. aeruginosa.  相似文献   

6.
The production of 1,3-propanediol (1,3-PD) was investigated with Klebsiella pneumoniae DSM 4799 using raw glycerol without purification obtained from a biodiesel production process. Fed-batch cultures with suspended cells revealed that 1,3-PD production was more effective when utilizing raw glycerol than pure glycerol (productivity after 47 h of fermentation, 0.84 g?L?1?h?1 versus 1.51 g?L?1?h?1 with pure and raw glycerol, respectively). In addition, more than 80 g/L of 1,3-PD was produced using raw glycerol; this is the highest 1,3-PD concentration reported thus far for K. pneumoniae using raw glycerol. Repeated fed-batch fermentation with cell immobilization in a fixed-bed reactor was performed to enhance 1,3-PD production. Production of 1,3-PD increased with the cycle number (1.06 g?L?1?h?1 versus 1.61 g?L?1?h?1 at the first and fourth cycle, respectively) due to successful cell immobilization. During 46 cycles of fed-batch fermentation taking place over 1,460 h, a stable and reproducible 1,3-PD production performance was observed with both pure and raw glycerol. Based on our results, repeated fed batch with immobilized cells is an efficient fermentor configuration, and raw glycerol can be utilized to produce 1,3-PD without inhibitory effects caused by accumulated impurities.  相似文献   

7.
Biosurfactant produced from Pseudomonas aeruginosa DSVP20 was evaluated for its potential to disrupt Candida albicans biofilm formed on polystyrene (PS) surfaces in this investigation. P. aeruginosa DSVP20 exhibited optimum production of biosurfactant (5.8 g?L?1) after 96 h of growth with an ability to reduce surface tension of the aqueous solution from 72 to 28 mN?m?1. Analysis of purified biosurfactant with FT-IR, 1H and 13C NMR and MALDI-TOF MS revealed it to be di-rhamnolipid (RL-2) in nature. Biofilm disrupting ability of RL-2 (0.16 mg?mL?1) on Candida cells when checked using XTT reduction assay revealed that about 50 % of the cells remain adhered to 96-well plate after 2 h of treatment, while up to 90 % reduction in pre-formed C. albicans biofilm on PS surface was observed with RL-2 (5.0 mg?mL?1) in a dose-dependent manner. Microscopic analyses (SEM and CLSM) further confirm the influence of RL-2 on disruption of Candida biofilm extracellular matrix on PS surface which can be exploited as a potential alternative to the available conventional therapies.  相似文献   

8.
A biosurfactant-producing thermophile was isolated from the Kahrizak landfill of Tehran and identified as a bacterium belonging to the genus Aneurinibacillus. A thermostable lipopeptide-type biosurfactant was purified from the culture medium of this bacterium and showed stability in the temperature range of 20–90 °C and pH range of 5–10. The produced biosurfactant could reduce the surface tension of water from 72 to 43 mN/m with a CMC of 1.21 mg/mL. The strain growing at a temperature of 45 °C produces a substantial amount of 5 g/L of biosurfactant in the medium supplemented with sunflower oil as the sole carbon source. Response surface methodology was employed to optimize the biosurfactant production using sunflower oil, sodium nitrate, and yeast extract as variables. The optimization resulted in 6.75 g/L biosurfactant production, i.e., 35 % improved as compared to the unoptimized condition. Thin-layer chromatography, FTIR spectroscopy, 1H-NMR spectroscopy, and biochemical composition analysis confirmed the lipopeptide structure of the biosurfactant.  相似文献   

9.
The production of antimicrobial metabolites by Paenibacillus polymyxa RNC-D was assessed. Two process variables, glucose and inoculum concentrations, were evaluated at different levels (5?C40 g L?1, and at ?? r = 2.5?C5.0 %, respectively), and their effects on biomass formation, minimal inhibitory concentration (MIC) against Escherichia coli, and surface tension reduction (STR) were studied. When the fermentation process was carried out under non-optimised conditions, the biomass, MIC, and STR achieved the following values: 0.6 g L?1, 1 g L?1, and 18.4 mN m?1, respectively. The optimum glucose (16 g L?1) and inoculum volume ratio (?? r = 5.0 %) were defined in order to maximise the biomass formation, with a low value of MIC and high STR of extract. The experiments carried out under optimal conditions showed the following values for the dependent variables: biomass concentration 2.05 g L?1, MIC 31.2 ??g mL?1, and STR 10.7 mN m?1, which represented improvement of 241.7 %, 96.9 %, and 41.9 % for the responses of biomass, MIC, and STR, respectively. This is the first recorded study on the optimisation of culture conditions for the production of antimicrobial metabolites of P. polymyxa RNC-D, and constitutes an important step in the development of strategies to modulate the production of antimicrobial molecules by this microorganism at elevated levels.  相似文献   

10.
Ten yeast strains were evaluated concerning their capabilities to assimilate biodiesel-derived glycerol in batch cultivation. The influence of glycerol concentration, temperature, pH and yeast extract concentration on biomass production was studied for the yeast selected. Further, the effect of agitation on glycerol utilization by the yeast Hansenula anomala was also studied. The yeast H. anomala CCT 2648 showed the highest biomass yield (0.30?g?g?1) and productivity (0.19?g?L?1?h?1). Citric acid, succinic acid, acetic acid and ethanol were found as the main metabolites produced. The increase of yeast extract concentration from 1 to 3?g?L?1 resulted in high biomass production. The highest biomass concentration (21?g?L?1), yield (0.45?g?g?1) and productivity (0.31?g?L?1?h?1), as well as ribonucleotide production (13.13?mg?g?1), were observed at 700?rpm and 0.5?vvm. These results demonstrated that glycerol from biodiesel production process showed to be a feasible substrate for producing biomass and ribonucleotides by yeast species.  相似文献   

11.
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   

12.
The study details the investigations on the ability of Lactobacillus plantarum CFR 2194, an isolate from kanjika, a rice-based ayurvedic fermented product, to produce biosurfactant. Surfactant production, as a function of fermentation time, indicates that the maximum production occurred at 72 h under stationary conditions. Isolation, partial purification, and characterization of the biosurfactant produced have been carried out, and Fourier transform infrared spectroscopy (FTIR) spectra demonstrated that biosurfactants were constituted by protein and polysaccharide fractions, i.e., possessed the structure typical of glycoprotein, which is affected by the medium composition and the phase of growth of the biosurfactant-synthesizing strain. Critical micelle concentration (cmc) of the biosurfactant was found to be 6 g l?1. The emulsification index (EI), emulsification activity (EA), and emulsion stability (ES) values of the biosurfactant have confirmed its emulsification property. Aqueous fractions of the produced biosurfactant exhibited a significant antimicrobial activity against the food-borne pathogenic species: Escherichia coli ATCC 31705, E. coli MTCC 108, Salmonella typhi, Yersinia enterocolitica MTCC 859, and Staphylococcus aureus F 722. More importantly, the biosurfactant from L. plantarum showed antiadhesive property against above food-borne pathogens. The results thus indicate the potential for developing strategies to prevent microbial colonization of food contact surfaces and health-care prosthesis using these biosurfactants.  相似文献   

13.
An efficient in vitro propagation method has been developed for the first time for Musa acuminata (AAA) cv. Vaibalhla, an economically important banana cultivar of Mizoram, India. Immature male flowers were used as explants. Murashige and Skoog’s (MS) medium supplemented with plant growth regulators (PGRs) were used for the regeneration process. Out of different PGR combinations, MS medium supplemented with 2 mg L?1 6-benzylaminopurine (BAP) + 0.5 mg L?1 α-naphthalene acetic acid (NAA) was optimal for production of white bud-like structures (WBLS). On this medium, explants produced the highest number of buds per explant (4.30). The highest percentage (77.77) and number (3.51) of shoot formation from each explants was observed in MS medium supplemented with 2 mg L?1 kinetin + 0.5 mg L?1 NAA. While MS medium supplemented with a combination of 2 mg L?1 BAP + 0.5 mg L?1 NAA showed the maximum shoot length (14.44 cm). Rooting efficiency of the shoots was highest in the MS basal medium without any PGRs. The plantlets were hardened successfully in the greenhouse with 96 % survival rate. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers were employed to assess the genetic stability of in vitro regenerated plantlets of M. acuminata (AAA) cv. Vaibalhla. Eight RAPD and 8 ISSR primers were successfully used for the analysis from the 40 RAPD and 30 ISSR primers screened initially. The amplified products were monomorphic across all the regenerated plants and were similar to the mother plant. The present standardised protocol will find application in mass production, conservation and genetic transformation studies of this commercially important banana.  相似文献   

14.
The inflorescences as explants for rapid propagation in vitro remained unknown in Populus euphratica Olivier. Here, we reported that multiple shoots were initiation from calli of both male and female inflorescences. The optimum medium for shoot induction from male inflorescences was lactose sulfite medium containing 1.0?mg?L?1 6-benzylaminopurine (BA) and 0.5?mg?L?1 ??-naphthalene acetic acid (NAA) or Murashige and Skoog (MS) medium containing 0.5?mg?L?1 BA and 0.2?mg?L?1 NAA. The optimum medium of shoot induction from female inflorescence calli was the MS medium containing 0.5?mg?L?1 BA and 0.2?mg?L?1 NAA. Rooting of regenerated shoots was obtained on 1/2 MS medium supplemented with 0.5??1.0?mg?L?1 indole-3-butyric acid (IBA) and the highest frequency rooting was on medium containing 0.5?mg?L?1 IBA. No shoots were obtained on medium without BA and NAA. Peroxidase (POD) activity was measured by polyacrylamide gel electrophoresis during shoot induction and differentiation stages. The results showed that two bands of POD (2a and 2b) activity appeared lowest during the early 8?days at the dedifferentiation phase of leaves inducing calli, whereas POD 2a, 2b activity appeared to be increasing at the homeochronous dedifferentiation phase of inflorescence. Five most intensive bands, POD 1a, 1b, 1c, 2a, and ab, appeared in 8th and 28th days at the redifferentiation phase during shoot morphogenesis. These results demonstrated that the POD was involved in shoot morphogenesis from both leaf and inflorescence explants of Populus euphratica.  相似文献   

15.
Inulin and glycerol were used as substrates for efficient erythritol and citric acid production by newly engineered Yarrowia lipolytica strains. Hydrolysis of inulin by the Y. lipolytica Wratislavia K1 strain was established by expressing the Kluyveromyces marxianus INU1 gene. Erythritol was produced in two stages: inulin was used for biomass formation, followed by erythritol biosynthesis initiated by glycerol addition. The highest titer of erythritol obtained, 120.9 g L?1 with the yield of 0.6 g g?1, was produced by the K1 INU 6 strain. Moreover, the K1 INU 6 strain in fed-batch culture produced a high amount of citric acid: 105.2 g L?1 after 235 h from 200 g L?1 of inulin. Maximum activity of inulinase during this culture was 14000 U g?1 of cell dry mass. The presented study proves the potential of new Y. lipolytica transformants for efficient erythritol and citric acid production from inexpensive raw materials such as inulin and glycerol.  相似文献   

16.
With the problems related to chemical methods of pyruvic acid (PA) synthesis, a fast-growing interest has been observed in research aiming at reducing the production cost of PA by applying biotechnological methods. This study aimed to investigate the potential applicability of Yarrowia lipolytica Wratislavia 1.31 yeast strain for valorisation of pure and crude glycerol through the production of industrially desired PA. Conditions required for the effective PA biosynthesis, i.e., pH value, thiamine concentration, agitation, and substrate concentration, were examined in batch and fed-batch cultivation modes. The efficient production of PA occurred under the limitation of thiamine (1 µg L?1) and was stimulated by moderate pH (4.5) and agitation (800 rev min?1) of the culture. Under optimal conditions, Y. lipolytica Wratislavia 1.31 was able to produce 85.2 g L?1 of PA with volumetric productivity of 0.90 g L?1 h?1. The yield of PA biosynthesis reached a high level of 1.03 g g?1. Obtained results confirmed the aptitude of Y. lipolytica yeast to produce high amounts of PA from simple glycerol-containing media. Presented process was very promising and might be considered as an attractive alternative for currently used chemical methods of PA synthesis.  相似文献   

17.
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   

18.
The production of biosurfactant by Rhodococcus erythropolis during the growth on glycerol was investigated. The process was carried out at 28°C in a 1.5-L bioreactor using glycerol as carbon source. The bioprocess was monitored through measurements of biosurfactant concentration and glycerol consumption. After 51 h of cultivation, 1.7 g/L of biosurfactant, surface, and interfacial tensions values (with n-hexadecane) of 43 and 15 mN/m, respectively, 67% of Emulsifying Index (E 24), and 94% of oil removal were obtained. The use of glycerol rather than what happens with hydrophobic carbon source allowed the release of the biosurfactant, originally associated to the cell wall.  相似文献   

19.
An animal protein-free medium composed of IPL-41 containing 6 g L?1 yeastolate ultrafiltrate, 10 g L?1 glucose, 2 g L?1 lactose, 5 g L?1 glutamine, 1% lipid emulsion, and 0.1% Pluronic F-68 was used for producing recombinant proteins in batch mode employing two cell lines, S2AcRVGP2k expressing the G glycoprotein from rabies virus (RVGP) and S2AcHBsAgHy-9C expressing the surface antigen of hepatitis B virus (HBsAg), both obtained from Drosophila melanogaster S2 cells. Growth of wild-type S2 cells was also evaluated in the same medium. Cell behavior in the tested medium was compared to that verified in Sf900 II®. The results show that in shake flasks, S2AcRVGP2k and S2AcHBsAgHy-9C cells reached around 2?×?107 cells mL?1 in both media. In supplemented IPL-41 and Sf900 II® media, S2AcRVGP2k cells produced 367 ng RVGP mL?1 and 638 ng RVGP mL?1, respectively, while S2AcHBsAgHy-9C cells correspondently produced 573 ng HBsAg mL?1 and 322 ng HBsAg mL?1 in the mentioned media. In stirred tanks, S2AcRVGP2k cells reached 3?×?107 cells mL?1 and produced up to 758 ng RVGP mL?1. In general, glucose was consumed by cells, while lactate and ammonia were produced.  相似文献   

20.
A reliable in vitro regeneration system for the economical and medicinally important Piper nigrum L. has been established. Callus and shoot regeneration was encouraged from leaf portions on Murashige and Skoog (MS) medium augmented with varied concentrations of plant growth regulators. A higher callus production (90 %) was observed in explants incubated on MS medium incorporated with 1.0 mg?L?1 6-benzyladenine (BA) along with 0.5 mg?L?1 gibberellic acid after 4 weeks of culture. Moreover, a callogenic response of 85 % was also recorded for 1.0 mg?L?1 BA in combination with 0.25 mg?L?1 α-naphthalene acetic acid (NAA) and 0.25 mg?L?1 2,4-dichlorophenoxyacetic acid or 0.5 mg?L?1 indole butyric acid (IBA) along with 0.25 mg?L?1 NAA and indole acetic acid. Subsequent sub-culturing of callus after 4 weeks of culture onto MS medium supplemented with 1.5 mg?L?1 thiodiazoran or 1.5 mg?L?1 IBA induced 100 % shoot response. Rooted plantlets were achieved on medium containing varied concentrations of auxins. The antioxidative enzyme activities [superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX)] revealed that significantly higher SOD was observed in regenerated plantlets than in other tissues. However, POD, CAT, and APX were higher in callus than in other tissues. A high-performance liquid chromatography (HPLC) fingerprint analysis protocol was established for quality control in different in vitro-regenerated tissues of P. nigrum L. During analysis, most of the common peaks represent the active principle “piperine.” The chemical contents, especially piperine, showed variation from callus culture to whole plantlet regeneration. Based on the deviation in chromatographic peaks, the in vitro-regenerated plantlets exhibit a nearly similar piperine profile to acclimated plantlets. The in vitro regeneration system and HPLC fingerprint analysis established here brought a novel approach to the quality control of in vitro plantlets, producing metabolites of interest with substantial applications for the conservation of germplasm.  相似文献   

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