Emulsifying activity and stability of a non-toxic bioemulsifier synthesized by Microbacterium sp. MC3B-10

• Published in: International journal of molecular sciences 2013-09, Vol.14 (9), p.18959-18972
• Main Authors: Camacho-Chab, Juan Carlos, Guézennec, Jean, Chan-Bacab, Manuel Jesús, Ríos-Leal, Elvira, Sinquin, Corinne, Muñiz-Salazar, Raquel, De la Rosa-García, Susana del C, Reyes-Estebanez, Manuela, Ortega-Morales, Benjamín Otto
• Format: Article
• Language: English
• Subjects: Actinomycetales - classification; Actinomycetales - metabolism; Animals; Artemia - drug effects; Artemia salina; Biodegradation, Environmental; bioemulsifier; Biopolymers; Bioremediation; Biotechnology; Carbohydrates; Chromatography; Cosmetics; Electronic mail systems; Emulsifying Agents - chemistry; Emulsifying Agents - metabolism; Emulsifying Agents - toxicity; emulsifying stability; Fatty acids; Hydrocarbons, Aromatic - chemistry; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Life Sciences; Lipids; Microbacterium; Microbacterium sp; Microorganisms; Molecular weight; non-toxic; Oils - chemistry; Oleic Acid - chemistry; Palmitic Acid - chemistry; Phylogeny; Polymers; Proteins; Sciences of the Universe; Stearic Acids - chemistry; Surfactants; Temperature; Toxicity
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms140918959

A previously reported bacterial bioemulsifier, here termed microbactan, was further analyzed to characterize its lipid component, molecular weight, ionic character and toxicity, along with its bioemulsifying potential for hydrophobic substrates at a range of temperatures, salinities and pH values. Analyses showed that microbactan is a high molecular weight (700 kDa), non-ionic molecule. Gas chromatography of the lipid fraction revealed the presence of palmitic, stearic, and oleic acids; thus microbactan may be considered a glycolipoprotein. Microbactan emulsified aromatic hydrocarbons and oils to various extents; the highest emulsification index was recorded against motor oil (96%). The stability of the microbactan-motor oil emulsion model reached its highest level (94%) at 50 °C, pH 10 and 3.5% NaCl content. It was not toxic to Artemia salina nauplii. Microbactan is, therefore, a non-toxic and non-ionic bioemulsifier of high molecular weight with affinity for a range of oily substrates. Comparative phylogenetic assessment of the 16S rDNA gene of Microbacterium sp. MC3B-10 with genes derived from other marine Microbacterium species suggested that this genus is well represented in coastal zones. The chemical nature and stability of the bioemulsifier suggest its potential application in bioremediation of marine environments and in cosmetics.