Biosurfactants – potential and applications

Biosurfactants are molecules that exhibit pronounced surface and emulsifying activities, produced by a variety of microorganisms. A host of interesting features of biosurfactants, such as higher biodegradability, lower toxicity, and effectiveness at extremes of temperature, pH and salinity; have led to a wide range of potential applications in the fields of oil recovery, environmental bioremediation, food processing and medicine. In spite of the immense potential of biosurfactants, their use still remains limited, possibly due to their high production and extraction costs, low yields in production processes and lack of information on their toxicity towards human systems [1]. The use and potential commercial application of biosurfactants in the medical field has increased during the past decade [2]. Their antibacterial, antifungal and antiviral activities make them relevant molecules for applications in combating many diseases and as therapeutic agents. In addition their role as anti-adhesive agents against several pathogens indicates their utility as suitable anti-adhesive coating agents for medical insertional materials leading to a reduction of a large number of hospital infections without the use of synthetic drugs and chemicals. The most promising alternative to turn its production competitive for industrial applications is the knowledge of the genes involved in their biosynthesis. Identification and isolation of those genes will allow enhanced production. Furthermore, modification of those genes by genetic engineering will result in the production of novel biosurfactants with specific novel properties. Medicinal and therapeutic perspectives of biosurfactants applications and future research plans will be presented

Biosurfactants production from cheese whey

Biosurfactants are molecules that exhibit pronounced surface and emulsifying activities, produced by a variety of microorganisms. A host of interesting features of biosurfactants, such as higher biodegradability, lower toxicity, and effectiveness at extremes of temperature, pH and salinity; have led to a wide range of potential applications in the fields of oil recovery, environmental bioremediation, food processing and medicine. In spite of the immense potential of biosurfactants, their use still remains limited, mainly due to their high production and extraction costs, low yields in production processes and lack of information on their toxicity towards human systems. However, the use of cheaper substrates and optimal growth and production conditions coupled with novel and efficient multistep downstream processing methods and the use of recombinant and mutant hyper producing microbial strains can make biosurfactant production economically feasible. Often, the amount and type of a raw material can contribute considerably to the production cost; it is estimated that raw materials account for 10 to 30% of the total production costs in most biotechnological processes. Thus, to reduce this cost it is desirable to use low-cost raw materials. One possibility explored extensively is the use of cheap and agro-based raw materials as substrates for biosurfactant production. A variety of cheap raw materials, including plant-derived oils, oil wastes, starchy substances, cheese whey and distillery wastes have been reported to support biosurfactant production. Future biosurfactant research should, therefore, be more focused on the economics of biosurfactant production processes, particularly through the use of alternative low-cost fermentative media. This review looks at the future perspectives of large-scale profitable production of biosurfactants

Development of low-cost culture media for effective biosurfactant production

In this work, biosurfactant production by Pseudomonas aeruginosa and Bacillus subtillis strains was optimized using low-cost substrates. The highest biosurfactant production (3.2 g/L) by the P. aeruginosa strain was obtained using a culture medium containing corn steep liquor (CSL) (10% (v/v)) and molasses (10% (w/v)), whereas the best biosurfactant production by the B. subtillis isolate (1.3 g/L) was obtained using a culture medium consisting of 10% (v/v) of CSL. Subsequently, for the B. subtillis strain, the effect of different metals (iron, manganese and magnesium) on biosurfactant production was evaluated. When the culture medium CSL 10% was supplemented with the optimum concentration of those metals simultaneously, the biosurfactant production was increased up to 4.8 g/L. The biosurfactant produced by the P. aeruginosa strain was characterized as a mixture of eight different rhamnolipid congeners, being the most abundant the mono-rhamnolipid Rha-C10-C10, and the biosurfactant produced by the B. subtillis isolate consisted of a mixture of C13-, C14- and C15-surfactin. Both biosurfactants exhibited a good performance in oil recovery assays when compared with chemical surfactants, suggesting their potential use as an alternative to traditional chemical surfactants in enhanced oil recovery or bioremediation

New microbial surface-active compounds: the ultimate alternative to chemical surfactants?

Surface active compounds (SACs) produced by microorganisms are attracting a pronounced interest due to their potential advantages over synthetic counterparts, and to the fact that they could replace some of the synthetics in many environmental and industrial applications. Bioemulsifier production by a Paenibacillus strain isolated from crude oil was studied. The bioemulsifier was produced using sucrose with and without adding hydrocarbons (paraffin or crude oil) under aerobic and anaerobic conditions at 40ºC. It formed stable emulsions with several hydrocarbons, exhibiting similar or better emulsifying activity when compared with chemical SACs, and its emulsifying ability was not affected by exposure to high salinities (up to 300 g/l), high temperatures (100-121ºC) or a wide range of pH values (2-13). In addition, it presented low toxicity and high biodegradability when compared with chemical surfactants, implying a greater environmental compatibility. A preliminary chemical characterization by Fourier Transform Infrared Spectroscopy (FT-IR), proton and carbon nuclear magnetic resonance (1H NMR and 13C CP-MAS NMR) and size exclusion chromatography indicated that the bioemulsifier is a low molecular weight oligosaccharide-lipid complex. To the best of our knowledge, bioemulsifier production by a Paenibacillus strain has not been previously reported. This is also the first description of a low molecular weight bioemulsifier. The features of this novel bioemulsifier make it an interesting biotechnological product for many environmental and industrial applications.Financial support from the projects BIOCLEAN-Desenvolvimento de produtos contendo surfactantes microbianos para limpeza e desinfeção de superfícies industriais e domésticas. QREN-n.º 2013/030215, and NCMICROBIOS -Desenvolvimento de bioprocessos usando microrganismos não convencionais para a produção de biosurfactantes - Convénio FCT-CNPq Nº 17/2013 – Ref.: Projecto nº 6818

Improved biosurfactant production by a Pseudomonas aeruginosa strain using agro-industrial wastes

Microbial surfactants are amphipathic molecules produced by a variety of microorganisms that exhibit pronounced surface and emulsifying activities. Biosurfactants can replace synthetic surfactants in environmental and industrial applications, such as bioremediation and microbial enhanced oil recovery. Furthermore, some biosurfactants have been reported as suitable alternatives to synthetic medicines and antimicrobial agents and may be used as effective therapeutic agents, due to their antibacterial, antifungal, antiviral and anti-adhesive activities. The main advantages of biosurfactants when compared with synthetic surfactants include their diversity, specificity, environmentally friendly nature, non-toxicity and high biodegradability, effectiveness at extreme temperatures or pH values, as well as their suitability for scale-up production. Many of the potential applications that have been considered for biosurfactants depend on whether they can be produced economically at large-scale. Several efforts have been conducted to reduce production costs, including the use of agro-industrial wastes as substrates, optimization of medium and culture conditions and efficient recovery processes. In this work, biosurfactant production by a Pseudomonas aeruginosa strain isolated from a crude oil sample was optimized using agro-industrial wastes. A culture medium containing corn step liquor (10% v/v) and molasses (10% w/v) led to the production of 5 g biosurfactant/l, which is about ten times the amount of biosurfactant produced when using LB medium. The crude biosurfactant reduced the surface tension of water to 31 mN/m and exhibited high emulsifying activity (60%), with a critical micelle concentration of 200 mg/l. Moreover, it showed antimicrobial activity against a broad range of Gram-positive and Gram-negative bacteria, as well as a high efficiency in removing oil from contaminated sand, when compared with chemical surfactants. The results obtained suggest the possibility of using this biosurfactant as an alternative to traditional chemical surfactants

Influência de açúcares complementares no peso molecular do dextrano produzido por fermentação com Leuconostoc mesenteroides NRRL B512(f). Case study: Produção de dextrano usando extracto de vagem de alfarroba e soro de queijo

[Exerto] O dextrano e a frutose têm muitas aplicações industriais. O dextrano é utilizado como expansor de volume sanguíneo, na indústria alimentar e como meio cromatográfico. A frutose é um açucar de baixo valor calórico. [...

Production of dextran and fructose from carob pod extract and cheese whey by Leuconostoc mesenteroides NRRL B512(f)

The production of dextran and fructose from carob pod extract (CPE) and cheese whey (CW) as carbon source by the bacterium Leuconostoc mesenteroides was investigated. The influence of secondary carbon sources (maltose, lactose and galactose) on dextran molecular weight and fermented broth viscosity were also studied. Significant changes were not observed in broth viscosity during dextran production at initial sucrose concentration of 20 and 120 g/l. Complementary sugars maltose, lactose and galactose together with sucrose promote production of dextran with fewer glucose units. Dextran molecular weight decreases from the range 1,890,000–10,000,000 to 240,000–400,000 Da when complementary sugars are present. Polydispersity was improved when complementary sugars were used. Fermentation using mixtures of carob pod extract and cheese whey confirm these results obtained for production of dextran. Final concentrations of dextran and fructose indicate that reaction yields were not affected. Carob pod and cheese whey can be successfully used as raw material in the fermentation system described. The maximum concentrations of dextran and fructose obtained using carob pod extract resulted in 8.56 and 7.78 g/l, respectively. Combined carob pod extract and cheese whey resulted in dextran and fructose concentrations of 7.23 and 6.98 g/l, respectively. The corresponding dextran mean molecular weight was 1,653,723 and 325,829.(undefined