Characterization and emulsification properties of rhamnolipid and sophorolipid biosurfactants and their applications

Due to their non-toxic nature, biodegradability and production from renewable resources, research has shown an increasing interest in the use of biosurfactants in a wide variety of applications. This paper reviews the characterization of rhamnolipid and sophorolipid biosurfactants based on their hydrophilicity/hydrophobicity and their ability to form microemulsions with a range of oils without additives. The use of the biosurfactants in applications such as detergency and vegetable oil extraction for biodiesel application is also discussed. Rhamnolipid was found to be a hydrophilic surfactant while sophorolipid was found to be very hydrophobic. Therefore, rhamnolipid and sophorolipid biosurfactants in mixtures showed robust performance in these applications.     

Environmental applications of biosurfactants: recent advances

Increasing public awareness of environmental pollution influences the search and development of technologies that help in clean up of organic and inorganic contaminants such as hydrocarbons and metals. An alternative and eco-friendly method of remediation technology of environments contaminated with these pollutants is the use of biosurfactants and biosurfactant-producing microorganisms. The diversity of biosurfactants makes them an attractive group of compounds for potential use in a wide variety of industrial and biotechnological applications. The purpose of this review is to provide a comprehensive overview of advances in the applications of biosurfactants and biosurfactant-producing microorganisms in hydrocarbon and metal remediation technologies.     

Surfactin生物表面活性剂及其驱油研究进展

表面活性素（surfactin）是一类由革兰氏阳性的枯草芽孢杆菌产生的脂肽（lipopeptide）型生物表面活性剂,因其具有优于化学合成表面活性剂的若干优点,如低毒性、高生物降解性、更好的环境相容性,且在极端环境下稳定性好,在提高石油采收率方面有较好的应用潜力,但是目前只有少数的生物表面活性剂可以大规模生产实现工业化应用。本文介绍了surfactin生物表面活性剂的化学结构和生物合成机制,并对其发酵生产过程的影响因素进行分析,为提高其生产经济性探索不同的策略,例如使用更便宜的原材料、优化培养基组分、优化反应器等,系统论述了surfactin生物表面活性剂的驱油机理和其与化学合成表面活性剂的复配研究,同时针对其应用时的不足之处提出研究新思路。     

生物表面活性剂驱油研究进展

第三次采油技术的发展促进了表面活性剂在油田生产中成熟而稳定的应用。与化学合成表面活性剂相比,生物表面活性剂具有无毒等优势,在近些年呈现出热点研究态势,部分成果业已得到应用。本文从生物表面活性剂的驱油机理、纯化、应用3个方面进行论述,并对其发展趋势进行了展望。在驱油机理方面,主要通过降低油水界面张力、乳化残油以及润湿性反转3种作用,保障开采后期的油藏采收率。在纯化方面,单一方法制备生物表面活性剂技术已经较为成熟,但这些方法均具有一定局限性;采用两种或多种方法联用,既可以降低纯化成本又可以提高产率,成为未来生物表面活性剂纯化技术的发展趋势。在应用方面,主要体现在与化学表面活性剂进行复配后定向注入油藏进行驱油;此外,近年来也开发出利用高效营养剂激活本源微生物,诱导其产生表面活性物质继而富集、驱油的新技术。     

Non-traditional Oils as Newer Feedstock for Rhamnolipids Production by <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> (ATCC 10145)

Oils and fats serve as one of the most important renewable feedstocks for various chemicals such as lubricants, textiles auxiliaries, biodiesel and surfactants. The oils have also proved themselves to be better substrates than glucose for production of biosurfactants such as rhamnolipids. Cost is major hindrance in the commercialization of these biosurfactants and fresh refined oils cannot be used for rhamnolipid production. Non-traditional oils such as jatropha oil, karanja oil and neem oil can be used as newer feedstock for the synthesis of rhamnolipids. Jatropha oil gave the highest production of rhamnolipids, 4.55 g/L in non-traditional oils and the rhamnolipid concentration was comparable to that of most common oils, sunflower oil giving 5.08 g/L of rhamnolipids. The jatropha oil contained mainly linoleic acid that showed the highest consumption rate as compared to oleic and palmitic acid. Neem oil produced a lower concentration of rhamnolipids (2.63 g/L) than other oils. Both monorhamnolipids and dirhamnolipids were synthesized using these oils. The product obtained can find high value specialty applications such as biomedical drug delivery and cosmetics.     

Electrokinetic remediation of gasoil contaminated soil enhanced by rhamnolipid

Electrokinetic remediation (EKR) has been investigated as one of the best technologies in soil remediation but its applications for organic contaminants have been limited due to low solubility of organics in water and their non-ionic nature. The use of biosurfactants may increase the remediation efficiency by increasing the solubility of organics. The purpose of the introduction of complexing substances is to enhance the EKR process forming complexes and/or increasing the electro-osmotic flow. In this study, the removal of gasoil from a soil using electrokinetic method was investigated in the presence of Rhamnolipid at various concentrations. EKR experiments were undertaken on a gasoil contaminated soil (20,000 ppm). Graphite carbon electrodes were used to provide an electrical direct current (ddp 30–60 V). Results showed that increasing the dose of Rhamnolipid, the efficiency of gasoil removal increased up to 86.7%. Moreover, the lower concentration of the gasoil observed in the liquid phase at the higher concentration of the biosurfactant clearly indicated that the Rhamnolipid addition can enhance gasoil biodegradation.     

Biosurfactant production by <Emphasis Type="Italic">Bacillus coagulans</Emphasis>

A new biosurfactant producer, Bacillus coagulans, was isolated from soil. Its 24-h-old culture broth had a low surface tension (27–29 mN/m). Optimization of cell growth of this bacterium led to maximal biosurfactant production with glucose or starch as the organic carbon source, a pH in the range 4.0–7.5, and incubation temperatures from 20 to 45°C. The crude biosurfactants obtained after neutralization and lyophilization of the acid precipitate yielded a minimal aqueous solution surface tension value of 29 mN/m and an interfacial tension value of 4.5 mN/m against hexadecane. The critical micelle concentration of the crude biosurfactants was 17 mg/L. Addition of NaCl to the aqueous solution of the crude product caused lowering of surface tension at both the aqueous solution-air and aqueous solution-n-hexadecane interfaces. These results indicate that the biosurfactants obtained have potential environmental and industrial applications and may have uses in microbially enhanced oil recovery.     

生物表面活性剂在油田中的应用

生物表面活性剂和化学表面活性剂一样 ,有亲水基团和疏水基团 ,它是由微生物生长在水不溶的物质中并以它为食物源产生的。在油田中 ,生物表面活性剂是微生物提高采收率的重要机理 ,具有水溶性好、反应产物均一、无毒、安全、驱油效果好等特点。生物表面活性剂有 4种类型 :糖脂类、磷脂类、脂蛋白或缩氨酸脂和聚合物类。大多数生物表面活性剂是糖脂 ,是碳水化合物连接在长链脂肪酸上。目前 ,室内研究主要是研究各种反应条件对微生物产生生物表面活性剂和生物表面活性剂对原油的影响。矿场实验有地面发酵和地下发酵两种形式。从生物表面活性剂的特点、筛选产生生物表面活性剂的菌种、生物表面活性剂的类型、室内研究、矿场实验和今后的发展方向等 6个方面综述了油田中的生物表面活性剂的应用     

生物表面活性剂的开发和应用

生物表面活性剂经过三十年的发展,现分为发酵法和酶法合成两个分支。生物表面活性剂的品种包括中性类脂、磷脂／脂肪酸、糖脂、含氨基酸类脂,聚合型和特殊型生物表面活性剂。     

Biosurfactants: Recent advances

Surfactants find applications in a wide variety of industrial processes. Biomolecules that are amphiphilic and partition preferentially at interfaces are classified as biosurfactants. In terms of surface activity, heat and pH stability, many biosurfactants are comparable to synthetic surfactants. Therefore, as the environmental compatibility is becoming an increasingly important factor in selecting industrial chemicals, the commercialization of biosurfactant is gaining much attention. In this paper, the general properties and functions of biosurfactants are introduced. Strategies for development of biosurfactant assay, enhanced biosurfactant production, large scale fermentation, and product recovery are discussed. Also discussed are recent advances in the genetic engineering of biosurfactant production. The potential applications of biosurfactants in industrial processes and bioremediation are presented. Finally, comments on the application of enzymes for the production of surfactants are also made.     

Utilization of Oil Industry Residues for the Production of Rhamnolipids by Pseudomonas indica

In the present work, a new strain Pseudomonas indica MTCC 3714 was studied for the production of biosurfactants using various rice‐bran oil industry residues viz. rice‐bran, de‐oiled rice‐bran, fatty acids and waxes. Among all the carbon sources, a maximum reduction in surface tension (26.4 mN/m) was observed when the media were supplemented with rice‐bran and the biosurfactant was recovered using the ultrasonication technique as one of the steps in the extraction process. Biosurfactants were obtained in yields of about 9.6 g/L using rice‐bran as the carbon source. The structure of the biosurfactants as characterized by FT‐IR, NMR (¹H and ¹³C) and LC–MS analysis revealed that the majority of the biosurfactants were di‐rhamnolipids. The biosurfactants produced were able to emulsify various hydrocarbons and showed excellent potential in microbial enhanced oil recovery, as it was able to recover kerosene up to 70 % in a sandpack test.     

Biosurfactants: Multifunctional Biomolecules of the 21st Century

In the era of global industrialisation, the exploration of natural resources has served as a source of experimentation for science and advanced technologies, giving rise to the manufacturing of products with high aggregate value in the world market, such as biosurfactants. Biosurfactants are amphiphilic microbial molecules with hydrophilic and hydrophobic moieties that partition at liquid/liquid, liquid/gas or liquid/solid interfaces. Such characteristics allow these biomolecules to play a key role in emulsification, foam formation, detergency and dispersal, which are desirable qualities in different industries. Biosurfactant production is considered one of the key technologies for development in the 21st century. Besides exerting a strong positive impact on the main global problems, biosurfactant production has considerable importance to the implantation of sustainable industrial processes, such as the use of renewable resources and “green” products. Biodegradability and low toxicity have led to the intensification of scientific studies on a wide range of industrial applications for biosurfactants in the field of bioremediation as well as the petroleum, food processing, health, chemical, agricultural and cosmetic industries. In this paper, we offer an extensive review regarding knowledge accumulated over the years and advances achieved in the incorporation of biomolecules in different industries.     

Isolation,characterization, and antifungal application of a biosurfactant produced by Enterobacter sp. MS16

Isolate MS16 obtained from diesel contaminated soil, identified as Enterobacter sp. using 16S rRNA gene analysis produced biosurfactant when grown on unconventional substrates like groundnut oil cake, sunflower oil, and molasses. Of these carbon substrates used, sunflower oil cake showed highest biosurfactant production (1.5 g/L) and reduction in surface tension (68%). The biosurfactant produced by MS16 efficiently emulsified various hydrocarbons. The carbohydrates and fatty acids of the biosurfactants were studied using TLC, FTIR, NMR, and GC‐MS. The carbohydrate composition as determined by GC‐MS of their alditol acetate derivatives showed the predominance of glucose, galactose and arabinose, and hydroxyl fatty acids of chain length of C₁₆ and C₁₈ on the basis of FAMEs analysis. Biosurfactant showed antifungal activity and inhibited the fungal spore germination. Practical applications : Enterobacter sp., MS16 produces a biosurfactant composed of carbohydrates and fatty acids which exhibits excellent surface active properties. Use of industrial wastes for biosurfactant production is economical and facilitates the industrial production of this biosurfactant which has potential antifungal activity.     

Biotechnology and the fats and oils industry — An overview

Biotechnology is the application of single or multicellular organisms and of associated or derived enzyme systems to the production of desirable products. Particular discussion has been made of the derivation of fats and oils from animals, plants and microorganisms. General consideration has been given to methods, primarily plant breeding and agronomic practices for the improvement of the quantity and quality of oil produced by soybean, rapeseed, palm and sunflower. The possible importance of yeasts, fungi and algae as sources of single cell oil has been examined. A particular role of these systems in the production of specialty oils has been suggested. Enzyme systems, either associated with the intact cell or in isolation, can be used to varying degrees of success in either a free or immobilized form. Particular reference has been made to application of these systems to reactions including specific hydrolysis of triacylglycerols, acylation of glycerol, interesterification of triacylglycerols, wax ester formation and steroid transformations. Consideration has been given to particular plants and microorganisms as sources of new fats and oils. The major impact of biotechnology on the industry is believed to be associated with the production of high value specialty products including cocoa butter substitutes, biosurfactants, waxes and various prostaglandin derivatives. General consideration has been given to the possible relative importance of plant and microbial systems, engineering and scale-up problems, and overall economics of present biotechnological procedures.     

脂肽类生物表面活性剂研究进展

脂肽是由微生物代谢产生的一类具有很强表面活性的生物表面活性剂,在医药、环境保护、化妆品和微生物采油等方面有良好的应用潜力。该文对脂肽的生产、分离、鉴定及应用进展进行了综述。引用文献45篇。     

Applications of nanotechnology in oil and gas industry: Progress and perspective

Nanotechnology has been successfully implemented in many applications, such as nanoelectronics, nanobiomedicine, and nanodevices. However, this technology has rarely been applied to the oil and gas industry, especially in upstream exploration and production. The oil and gas industry needs to improve oil recovery and exploit unconventional resources. The cost of research and oil production is under immense pressure, and it is becoming more difficult to justify such investment when the crude oil price is weak and depressed. There is a widespread belief that nanotechnology may be exploited to develop novel nanomaterials with enhanced performance to combat these technological barriers. Increasing funding resources from governmental and global oil industry have been allocated to exploration, drilling, production, refining, and wastewater treatment. For example, nanosensors allow for precise measurement of reservoir conditions. Nanofluids prepared using functional nanomaterials may exhibit better performance in oil production processes, and nanocatalysts have improved the efficiency in oil refining and petrochemical processes. Nanomembranes enhance oil, water and gas separation, oil and gas purification, and the removal of impurities from wastewater. Functional nanomaterials can play an important role in the production of smart, reliable, and more durable equipment. In this review paper, we summarize the research progress and prospective applications of nanotechnology and nanomaterials in the oil and gas industry.     

Jatropha oil and karanja oil as carbon sources for production of sophorolipids

Biosurfactants like sophorolipids (SL) are mild and environmentally friendly surfactants to be used in cosmetics and health care products. In addition to surfactant properties, SL also possess antimicrobial and skin healing properties. SL are produced by microbial fermentation using refined vegetable oils with glucose as a carbon source. This affects the economics of the production of SL. In the present work, non‐traditional oils like jatropha oil, karanja oil, and neem oil were used as newer feedstock for fermentative production of SL using Starmerella bombicola (ATCC 22214). In the fermentation, jatropha oil and karanja oil gave 6.0 and 7.6 g/L of SL (mainly lactonic form), respectively. HPLC, liquid chromatography–mass spectrometer, and ¹H NMR of crude SL obtained from fermentation broth showed lactonic form of two major SL. Oleic acid and linoleic acid were preferentially consumed over other fatty acids by the organism. Neem oil gave lower yield, i.e., 2.63 g/L of SL (mainly acidic form). Practical applications: Jatropha oil and karanja oil are one of the non‐traditional oils grown wildly in India that have large potential that is still to be explored. These oils contain non‐glycerides components that exclude their use as edible oil. These oils can be used as substrate for SL that can find novel applications like in soil remediation, skin care production, antimicrobial agents, low foaming detergents, and food additives. The current study has provided proof of concept work that has indicated the potential of these oils to be used as substrate for SL. It has opened new avenues and there is further scope to improve the yield by validating the process parameters like aeration rate, residual substrate recycle and pH control.     

特种表面活性剂和功能性表面活性剂(Ⅶ)——生物表面活性剂的性能及应用研究进展

简要介绍了生物表面活性剂的分类及其合成方法;较详细地介绍了生物表面活性剂与化学合成表面活性剂相似和优于化学合成表面活性剂的特性以及生物表面活性剂的生理学功能;重点阐述了生物表面活性剂在石油工业、环境工程、食品工业、化妆品工业及医学领域等方面的应用现状;最后展望了生物表面活性剂的应用前景。     

Utilization of molasses for biosurfactant production by two Bacillus strains at thermophilic conditions

Traditionally, biosurfactants have been produced from hydrocarbons. Some possible substitutes for microbial growth and biosurfactant production include urban wastes, peat hydrolysate, and agro-industrial by-products. Molasses, a nonconventional substrate (agro-industrial by-product) can also be used for biosurfactant production. It has been utilized by two strains of Bacillus subtilis (MTCC 2423 and MTCC1427) for biosurfactant production and growth at 45°C. As a result of biosurfactant accumulation, the surface tension of the medium was lowered to 29 and 31 dynes/cm by the two strains, respectively. This is the first report of biosurfactant production by strains of B. subtilis at 45°C. Potential application of the biosurfactant in microbial enhanced oil recovery is also presented.     

Rhamnolipid synthesis and production with diverse resources

Rhamnolipids are one of the most effective biosurfactants that are of great interest in industrial applications such as enhancing oil recovery, health care, cosmetics, pharmaceutical processes, food processing, detergents for protein folding, and bioremediation due to their unique characteristics such as low toxicity, surface active property to reduce surface/interfacial tensions, and excellent biodegradability. The genes and metabolic pathways for rhamnolipid synthesis have been well elucidated, but its cost-effective production is still challenging. Pseudomonas aeruginosa, the most powerful rhamnolipid producer, is an opportunistic pathogen, which limits its large scale production and applications. Rhamnolipid production using engineered strains other than Pseudomonas aeruginosa such as E. coli and Pseudomonas putida has received much attention. The highest yield of rhamnolipids is achieved when oil-type carbon sources are used, but using cheaper and renewable carbon sources such as lignocellulose would be an attractive strategy to reduce the production cost of rhamnolipids for various industrial applications.

Open image in new window