Production and characterization of bioemulsifiers from Acinetobacter strains isolated from lipid-rich wastewater

Abstract

In this study, two indigenous bacterial strains (Ab9-ES and Ab33-ES) isolated from lipid-rich wastewater showed potential to produce bioemulsifier in the presence of 2% (v/v) olive oil as a carbon source. These bacterial strains were identified as Acinetobacter sp. Ab9-ES and Acinetobacter sp. Ab33-ES by polymerase chain reaction and analysis of 16S rRNA gene sequences. Bioemulsifier production by these strains was found to be growth-linked. Maximum emulsifying activities (83.8% and 80.8%) were recorded from strains Ab9-ES and Ab33-ES, respectively. Bioemulsifier yields of 4.52 g/L and 4.31 g/L were obtained from strains Ab9-ES (XB9) and Ab33-ES (YB33), respectively. Fourier-transform infrared spectroscopic analysis revealed the glycoprotein nature of the bioemulsifiers. The bioemulsifiers formed stable emulsions only in the presence of edible oils. Maximum emulsifying activities of 79.6% (XB9) and 67.9% (YB33) were recorded in the presence of sunflower oil. The bioemulsifiers were found to be stable at a broad range of temperature (4-121 °C), moderate pH (5.0-10.0) and salinity (1-6%). In addition, bioemulsifier XB9 showed maximum emulsifying activities (77.3%, 74.5%, and 74.9%) at optimum temperature (50 °C), pH (7.0), and NaCl concentration (3%), respectively. On the contrary, YB33 demonstrated highest activities (73.6%, 72%, and 61.2%) at optimum conditions of 70 °C, pH 7.0, and NaCl concentration of 5%, respectively. Findings from this study suggest the potential biotechnological applications of the bioemulsifiers, especially in the remediation of oil-polluted sites.

Production and characterization of bioemulsifier by Parapedobacter indicus

“…For extraction of BE, 72 h incubated bacterial culture supernatant was used. One part of the culture supernatant was mixed with three parts of chilled ethanol for precipitation, which was followed by overnight incubation at 4°C ( Adetunji and Olaniran, 2019 ). The precipitated BE was dialyzed in a cellulose tube membrane (molecular weight cut off 12,000–14,000 Daltons; Hi-media, India) for 48 h against distilled water, followed by lyophilization.…”

Biodegradation of crude oil present in wastewaters: evaluation of biosurfactant production and catechol 2,3 dioxygenase activity

“…The BS production during the hydrocarbon biodegradation process was determined using two methodologies: emulsification capacity and oil displacement (Adetunji & Olaniran, 2019). The formation of BS was analyzed through the correlation between product and substrate, according to Mu et al (2006).…”

Surface-Active Compounds Produced by Microorganisms: Promising Molecules for the Development of Antimicrobial, Anti-Inflammatory, and Healing Agents

“…Bioemulsifiers, which are synthesized by bacteria, yeasts, and filamentous fungi, can be isolated from contaminated soil, mangroves, seawater, freshwater, and human skin [ 50 , 51 , 52 , 53 ]. The most studied polymeric BEs include emulsan, alasan, liposan, mannoprotein, and other polysaccharide-protein complexes.…”