Identification and characterization of bioemulsifier-producing yeasts isolated from effluents of a dairy industry

Abstract

New bioemulsifier-producing yeasts were isolated from the biological wastewater treatment plant of a dairy industry. Of the 31 bioemulsifier-producing strains, 12 showed emulsifying activity after 2months of incubation, with E(24) values ranging from 7% to 78%. However, only Trichosporon loubieri CLV20, Geotrichum sp. CLOA40, and T. montevideense CLOA70 exhibited high emulsion-stabilizing capacity, with E(24) values of 78%, 67%, and 66%, respectively. These isolates were shown to induce a strong emulsion stabilizing activity rather than the reduction of the interfacial tension. These strains exhibited similar growth rates in the exponential growth phase, with a clear acceleration after 24h and stabilization of the activity after 144h. Emulsification and stability properties of the bioemulsifiers were compared to those of commercial surfactants after the addition of NaCl and exposure to temperature of 100 degrees C. The compounds produced by the isolates appeared to be lipid-polysaccharide complexes. Gas chromatograph analysis of the lipidic fraction of the bioemulsifiers from CLV20, CLOA40, and CLOA70 shows the prevalence of (9Z,12Z)-octadeca-9,12-dienoic acid, in concentrations of 42.8%, 25.9%, and 49.8%, respectively. The carbohydrate composition, as determined by GC-MS of their alditol acetate derivatives, showed a predominance of mannose, galactose, xylose and arabinose.

Bioconversion of biodiesel refinery waste in the bioemulsifier by Trichosporon mycotoxinivorans CLA2

“…It was recently reported that yeast strains of the genus Trichosporon and Geotrichum have the ability to produce bioemulsifiers that are able to emulsify toluene. These SACs are produced in culture medium supplemented with sunflower oil, and the bioemulsifier compounds contain (9Z,12Z)-octadeca-9,12-dienoic acid and mannose, galactose, xylose and arabinose monosaccharides [12]. …”

Bioactivity of the compounds isolated from Blepharocalyx salicifolius

“…The compound 2, (2E)-1-(4´-hydroxy-2´,6´-dimethoxy-3´,5´-dimethylphenyl)-3-phenylprop-2-en-1-one, showed similar structure to 1, seems to be an unedited substance. The compounds 3-4, isolated as pale yellow solids, were elucidated by means of NMR data, hydrolysis, peracetylation and GC/MS analysis (Cota et al, 2008;Monteiro et al,2009;Monteiro et al, 2010). It was possible to confirm the identity of the sugar moiety as rhamnose for 3 (Figure 1) and arabinose for 4 (Figure 2).…”

Microbiotechnology Based Surfactants and Their Applications

“…Bioemulsifiers are able to stabilize emulsions by increasing their kinetic stability and this property has increased their usefulness in the cosmetics, food, pharmaceutical and petroleum industries. Reports have shown that the efficient emulsifying activity of bioemulsifiers is a function of their chemical composition (Calvo et al, 2009;Monteiro et al, 2010). According to Willumsen and Karlson (1997), surface active biomolecules are categorized into surfactants and emulsifiers, while surfactants play the role of surface tension reduction, emulsifiers are involved in formation and stabilization of emulsions.…”

“…Halomonas eurihalina produces an exopolysaacharide (EPS) that acids and proteins produced by Klebsiella sp. On a general note bioemulsifiers have been associated with a number of potential applications including: remediation of oil polluted water and soil; enhanced oil recovery and clean-up of oil contaminated vessels and machineries; heavy metal removal (Monteiro et al, 2010;Zheng et al, 2012;Panjiar et al, 2014); formation of stable emulsions in food and cosmetics industries ; and therapeutic activities (antibacterial, antifungal, pesticidal and herbicidal agents) (Ahmed and Hassan, 2013). The physico-chemical properties of bioemulsifiers and biosurfactants are presented in Table 1.…”

“…The emulsifying potential of surface active compounds from different yeasts showing no reduction in surface tension, has been evaluated using the emulsification index test (Amaral et al, 2006;Monteiro et al, 2010). Toledo et al (2008) reported the growth and production of exopolymers by three bacteria, Bacillus subtilis 28, Alcaligenes faecalis 212, and Enterobacter sp.…”