Emulsifying activity and stability of a non-toxic bioemulsifier synthesized by Microbacterium sp. MC3B-10.
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.
Center of Environmental Microbiology and Biotechnology, Autonomous University of Campeche, Colonia Buenavista, San Francisco de Campeche 24039, Campeche, Mexico. beortega@uacam.mx.
Juan Carlos
JC
Camacho-Chab
Jean
J
Guézennec
Manuel Jesús
MJ
Chan-Bacab
Elvira
E
Ríos-Leal
Corinne
C
Sinquin
Raquel
R
Muñiz-Salazar
Susana del C
Sdel C
De la Rosa-García
Manuela
M
Reyes-Estebanez
Benjamín Otto
BO
Ortega-Morales
D000192:Actinomycetales / Q000145:classification / Q000378:metabolism*; D000818:Animals; D001156:Artemia / Q000187:drug effects; D001673:Biodegradation, Environmental; D045703:Emulsifying Agents / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D006841:Hydrocarbons, Aromatic / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D009821:Oils / Q000737:chemistry; D019301:Oleic Acid / Q000737:chemistry; D019308:Palmitic Acid / Q000737:chemistry; D010802:Phylogeny; D013229:Stearic Acids / Q000737:chemistry; D013696:Temperature
D045703:Emulsifying Agents; D006841:Hydrocarbons, Aromatic; D009821:Oils; D013229:Stearic Acids; D019301:Oleic Acid; D019308:Palmitic Acid; C031183:stearic acid