Biosurfactant production by Corynebacterium kutscheri from waste motor lubricant oil and peanut oil cake

AIM: Production and characterization of biosurfactant from renewable sources. METHODS AND RESULTS: Biosurfactant production was carried out in 3-l fermentor using waste motor lubricant oil and peanut oil cake. Maximum biomass (9.8 mg ml(-l)) and biosurfactant production (6.4 mg ml(-l)) occurred with peanut oil cake at 120 and 132 h, respectively. Chemical characterization of the biosurfactant revealed that it is a glycolipopeptide with chemical composition of carbohydrate (40%), lipid (27%) and protein (29%). The biosurfactant is able to emulsify waste motor lubricant oil, crude oil, peanut oil, kerosene, diesel, xylene, naphthalene and anthracene; the emulsification activity was comparatively higher than the activity found with Triton X-100. CONCLUSION: This study indicates the possibility of biosurfactant production using renewable, relatively inexpensive and easily available resources like waste motor lubricant oil and peanut oil cake. Emulsification activity found with the biosurfactant against different hydrocarbons showed the possibility of the application of biosurfactants against diverse hydrocarbon pollution. SIGNIFICANCE AND IMPACT OF THE STUDY: The data obtained from the study could be useful for large-scale biosurfactant production using economically cheaper substrates. Information obtained in emulsification activity and laboratory-scale experiment on bioremediation inferred that bioremediation of hydrocarbon-polluted sites may be treated with biosurfactants or the bacteria that produces it.     

Biosurfactant production by Pseudomonas aeruginosa A41 using palm oil as carbon source

Biosurfactant production by Pseudomonas aeruginosa A41, a strain isolated from seawater in the gulf of Thailand, was examined when grown in defined medium containing 2% vegetable oil or fatty acid as a carbon source in the presence of vitamins, trace elements and 0.4% NH(4)NO(3), at pH 7 and 30 degrees C with 200 rpm-shaking for 7 days. The yield of biosurfactant steadily increased even after a stationary phase. Under such conditions the surface tension of the medium was lowered from 55-70 mN/m to 27.8-30 mN/m with every carbon source tested. However, types of carbon sources were found to affect biosurfactant yield. The yields of rhamnolipid biosurfactant were 6.58 g/L, 2.91 g/L and 2.93 g/L determined as rhamnose content when olive oil, palm oil and coconut oil, respectively, were used as a carbon source. Among them, biosurfactant obtained from palm oil was the best in lowering surface tension of the medium. Increase in biosurfactant activities in terms of oil displacement test and rhamnose content were observed to be higher with shorter chain fatty acids than that of the longer chains (C12>C14>C16). In addition, we found that C18:2, highly unsaturated fatty acid, showed higher oil displacement activity and rhamnose content than that of C18:1. The optimal oil displacement activity was found at pH 7-9 and in the presence of 0.5-3% NaCl. The oil displacement activity was stable to temperatures up to 100 degrees C for 15 h. Surface tension reduction activity was relatively stable at pH 2-12 and 0-5% of NaCl. Emusification activity tested with various types of hydrocarbons and vegetable oils showed similarity of up to 60% stability. The partially purified biosurfactant via TLC and silica gel column chromatography gave three main peaks on HPLC with mass spectra of 527, 272, and 661 m/z respectively, corresponding to sodium-monorhamnodecanoate, hydroxyhexadecanoic acid and an unknown compound, respectively.     

Biosurfactant production by thermophilic dairy streptococci

Biosurfactant production of eight Streptococcus thermophilus strains, isolated from heat exchanger plates in the downstream side of the regenerator section of pasteurizers in the dairy industry has been measured using axisymmetric drop shape analysis by profile (ADSA-P). Strains were grown in M17 broth with either lactose, saccharose or glucose added. After harvesting, cells were suspended in water or in 10 mm potassium phosphate buffer, pH 7.0, and suspension droplets were put on a piece of FEP-Teflon. Changes in droplet profile were analysed by ADSA-P to yield the surface tension decrease due to biosurfactant production as a function of time. Surface tension decreases larger than 8 mJ·m^–2 were taken as indicative of biosurfactant production. Only five strains produced biosurfactants in water, solely when saccharose was added to the growth medium. In buffer, all strains produced biosurfactants and production was generally greater than in water. Also, most strains suspended in buffer produced maximally when saccharose was added to the growth medium, whereas one strain produced maximally in buffer upon the addition of glucose. Four strains suspended in buffer produced biosurfactants when glucose was added and only two strains when lactose was added. The possible role of these biosurfactants as anti-adhesives in the dairy industry and for the survival of these strains in natural systems is discussed.Correspondence to: H. J. Busscher     

Biosurfactant production by two isolates ofPseudomonas aeruginosa

Two strains of biosurfactant-producing bacteria, identified asPseudomonas aeruginosa, were isolated from injection water and crude oil-associated water in Venezuelan oil fields. Both biosurfactants resembled rhamnolipids and produced stable emulsions of heavy and extra-heavy crude oils, reducing the surface tension of water from 72 to 28 dynes/cm. Tenso-active properties of the biosurfactants were not affected by pH, temperature, salinity or Ca²⁺ or Mg²⁺ at concentrations in excess of those found in many oil reservoirs in Venezuela.     

Biosurfactant production: emerging trends and promising strategies

Biosurfactants are economically most sought after biotechnological compounds of the 21st century. However, inefficient bioprocessing has mitigated the economical commercial production of these compounds. Although much work is being done on the use of low-cost substrates for their production, a paucity of literature exists on the upcoming bioprocess optimization strategies and their successes and potential for economical biosurfactant production. This review discusses some of the latest developments and most promising strategies to enhance and economize the biosurfactant production process. Recent market analysis, developments in the field of optimally formulated cost credit substrates for enhanced product formation and subsequent process economization are few of the critical aspects highlighted here. Use of nanoparticles and coproduction of biosurfactant along with other commercially important compounds like enzymes, are other upcoming bioprocess intensification strategies. The recent developments discussed here would not only give an overview of pertinent parameters for economic biosurfactant production but would also bring to fore multiple strategies that would open up new avenues of research on biosurfactant production. This would go a long way in making biosurfactants a commercially successful compound of the current century.     

Biosurfactant production by Pseudomonas aeruginosaGS3 from molasses

Patterns of long-chain faecal fatty acids were studied by gas–liquid chromatography in 55 newborn infants in a neonatal intensive care unit. Decreased fractions of fatty acid C16 : 1⁹ and increased fractions of C16 : 0 and C17 : 0 were associated with the occurrence of abdominal distension. Decreased fractions of C16 : 1⁹ and C18 : 2^9,1 were associated with diarrhoea. Flatulence was found in infants who had relatively smaller amounts of fatty acids C17 : 0D and C15 : 0 in their faecal samples. The differences in the patterns of faecal fatty acids are due to differences in bacterial flora. The results support the hypothesis that the initial intestinal colonization plays a role in the later gastrointestinal signs of newborn infants.     

Biosurfactant production using molasses and whey under thermophilic conditions

Biosurfactant production was studied by Bacillus licheniformis K51, B. subtilis 20B, B. subtilis R1 and Bacillus strain HS3 using molasses or cheese whey as a sole source of nutrition at 45 degrees C. The isolates were able to grow and produce biosurfactant under shaking as well as static conditions. Maximum biosurfactant production was achieved with molasses at 5.0-7.0% (w/v). The biosurfactant retained its surface-active properties after incubation at 80 degrees C at a wide range of pH values and salt concentrations for nine days. Oil displacement experiments in sand pack columns with crude oil showed 25-33% recovery of residual oil.     

Biosurfactant production by a thermophilic Bacillus subtilis strain

A strain of Bacillus subtilis was able to grow and produce a biosurfactant on 2% sucrose at 45°C. As a result of biosurfactant synthesis the surface tension of the medium was reduced from 68 dynes cm⁻¹ to 28 dynes cm⁻¹. The strain had the capacity to produce the biosurfactant at high NaCl concentrations (4%) and a wide range of pH (4.5–10.5). The biosurfactant retained its surface-active properties after heating at 100°C for 2 h and at different pH values (4.5–10.5). A maximum amount of biosurfactant was produced when urea or nitrate ions were supplied as nitrogen source. The use of the biosurfactant at high temperatures, acidic, alkaline and saline environments is discussed. As a result of its action, 62% of oil in a sand pack column could be recovered, indicating its potential application in microbiologically enhanced oil recovery. Received 28 March 1996/ Accepted in revised form 16 September 1996     

Biosurfactant production by a new Pseudomonas putida strain

Observation of both tensio-active and emulsifying activities indicated that biosurfactants were produced by the newly isolated and promising strain Pseudomonas putida 21BN. The biosurfactants were identified as rhamnolipids, the amphiphilic surface-active glycolipids usually secreted by Pseudomonas spp. Their production was observed when the strain was grown on soluble substrates, such as glucose or on poorly soluble substrates, such as hexadecane, reaching values of 1.2 g l(-1). When grown on hexadecane as the sole carbon source the biosurfactant lowered the surface tension of the medium to 29 mN m(-1) and formed stable and compact emulsions with emulsifying activity of 69%.     

Biosurfactant production by Pseudomonas fluorescens 378: growth and product characteristics

Summary An isolate of Pseudomonas fluorescens, strain 378 was shown to produce a novel surface active compound (code name AP-6). The compound is unique in being a high molecular weight compound but has, in some aspects, properties of a low molecular weight surfactant. The product is extracellular and its formation appeared to be partly growth-associated. Using a semisynthetic medium, fermentor cultivations were performed in the pH range 6.8–8.4. The product yield was optimal at pH 8.0 and gave a final concentration of 210 times critical micelle dilution. At higher pH, specific growth rate, final biomass and product concentration decreased. It consists mainly of carbohydrates and protein, the molecular weight is 1×10⁶ and the isoelectric point is pH 9.1.The surface tension of an aqueous solution reached 27 mN/m which is a very low value even compared to other surfactants of considerably lower size and the critical micelle concentration was less than 10 mg/l in 0.9% (w/v) NaCl. The kinetics of the adsorption process at the air-water interface was studied using the drop volume technique, and the reaction was found to be rapid, considering the size of the molecule. A concentration as low as 0.025 g/l reached a surface tension of 30 mN/m within 70 s.     

Biosurfactant production by Pseudomonas aeruginosa SP4 using sequencing batch reactors: effects of oil loading rate and cycle time

In this present study, sequencing batch reactors (SBRs) were used for biosurfactant production from Pseudomonasaeruginosa SP4, which was isolated from petroleum-contaminated soil in Thailand. Two identical lab-scale aerobic SBR units were operated at a constant temperature of 37 degrees C, and a mineral medium (MM) with palm oil was used as the culture medium. The effects of oil loading rate (OLR) and cycle time on the biosurfactant production were studied. The results indicated that the optimum conditions for the biosurfactant production were at an OLR of 2 kg/m(3)days and a cycle time of 2 days/cycle, which provided a surface tension reduction of 59%, a chemical oxygen demand (COD) removal of 90%, and an oil removal of 97%. Under the optimum conditions, it was found that the biosurfactant production was maximized at an aeration time of 40 h. These preliminary results suggest that the SBR can potentially be adapted for biosurfactant production, and perhaps further developed, potentially for large-scale biosurfactant production.     

Biosurfactant production and hydrocarbon-degradation by halotolerant and thermotolerant Pseudomonas sp.

A hydrocarbon degrading and biosurfactant producing, strain DHT2, was isolated from oil-contaminated soil. The organism grew and produced biosurfactant when cultured in variety of substrates at salinities up to 6 g l⁻¹ and temperatures up to 45°C. It was capable of utilizing crude oil, fuels, alkanes and PAHs as carbon source across the wide range of temperature (30–45°C) and salinity (0–6%). Over the range evaluated, the salinity and temperature did not influence the degradation of hydrocarbon and biosurfactant productions. Isolate DHT2 was identified as Pseudomonas aeruginosa by analysis of 16S rRNA sequences (100% homology) and biochemical analysis. PCR and DNA hybridization studies revealed that enzymes involved in PAH metabolism were related to the naphthalene dioxygenase pathway. Observation of both tensio-active and emulsifying activities indicated that biosurfactants were produced by DHT2 during growth on both, water miscible and immiscible substrates, including PAH. The biosurfactants lowered the surface tension of medium from 54.9 to 30.2 dN/cm and formed a stable emulsion. The biosurfactant produced by the organism emulsified a range of hydrocarbons with hexadecane as best substrate and toluene was the poorest. These findings further indicate that the isolate could be useful for bioremediation and bio-refining application in petroleum industry.     

烟碱降解菌以烷烃为碳源产生物表面活性剂的研究

通过测定发酵过程中菌体浓度和发酵上清液的表面张力,研究了烷烃碳源和发酵条件对烟碱降解菌(Ochrobactrum sp.)产生物表面活性剂的影响。结果表明,菌株Ochrobactrum sp.以十三烷和十六烷为碳源生长较好,而利用液体石蜡可产生较多生物表面活性剂。以2%液体石蜡为碳源,装液量为40%(250 m L三角瓶),于30℃,120 r/min培养4 d时,发酵液表面张力能降低至42.1m N/m。     

Cephalosporin C production in a stirred tank reactor

Summary Cephalosporin C was produced with the moldCephalosporium acremonium in a 20 1 stirred tank reactor with 100 kg/m³ peanut flour in fed-batch operation. The growth and product formation was followed by on-line analysis of the broth composition. The cell concentration was estimated from the RNA-content of the cells. By optimization of the fed-batch operation and by increasing the phosphate content in the broth, a final cephalosporin C concentration of 12 kg/m³ was attained.Nomenclature CPC cephalosphorin C - DAC deacetylcephalosporin C - DAOC deacetoxycephalosporin C - k _L a volumetric mass transfer coefficient - MMBS 2-Hydroxy-4-methylmercaptobutyric acid - PABAH p-Hydroxybenzoicacidhydrazid - RNA ribonucleic acid - RQ respiratory quotient - oxygen transfer rate - CO₂-production rate - t fermentation time     

Biosurfactant production and growth kinetics of bacteria in a designer marine medium: improved physiochemical properties

A combinatorial screening strategy was adopted for the development of a suitable medium for enhanced biosurfactant production by a marine strain. As a result, a modified marine medium (MMM) was developed, which contained urea and strontium chloride besides other salts important for the growth of marine bacteria. This medium supported growth, evident from a higher maximum growth rate value of 0.42 h(-1) and an enhanced biosurfactant production of 2.58 g/L. The critical micelle concentration (CMC) was determined for the biosurfactants obtained from all tested media combinations. The biosurfactant produced with this medium was stable at high temperature (100 °C), a wide range of pH (5-11) and salt concentration of 5-35%. The emulsifying activity and stability of the biosurfactant obtained using MMM was better than the biosurfactant obtained using conventional media. This biosurfactant with improved physiochemical properties is suitable for a wide range of applications in industry and for marine environmental cleaning.     

Biosurfactant production by Pseudomonas sp. and its role in aqueous phase partitioning and biodegradation of chlorpyrifos

Aim:  To study the effect of biosurfactant on aqueous phase solubility and biodegradation of chlorpyrifos.
Methods and Results:  A Pseudomonas sp. (ChlD), isolated from agricultural soil by enrichment culture technique in the presence of chlorpyrifos, was capable of producing biosurfactant (rhamnolipids) and degrading chlorpyrifos (0·01 g l⁻¹). The partially purified rhamnolipid biosurfactant preparation, having a CMC of 0·2 g l⁻¹, was evaluated for its ability to enhance aqueous phase partitioning and degradation of chlorpyrifos (0·01 g l⁻¹) by ChlD strain. The best degradation efficiency was observed at 0·1 g l⁻¹ supplement of biosurfactant, as validated by GC and HPLC studies.
Conclusion:  The addition of biosurfactant at 0·1 g l⁻¹ resulted in more than 98% degradation of chlorpyrifos when compared to 84% in the absence of biosurfactant after 120-h incubation.
Significance and Impact of the Study:  This first report, to the best of our knowledge, on enhanced degradation of chlorpyrifos in the presence of biosurfactant(s), would help in developing bioremediation protocols to counter accumulation of organophosphates to toxic/carcinogenic levels in environment.