Release Time:2019-03-13  Hits:

Indexed by: Journal Article

Date of Publication: 2016-09-01

Journal: ANNALS OF MICROBIOLOGY

Included Journals: Scopus、SCIE

Volume: 66

Issue: 3

Page Number: 1145-1156

ISSN: 1590-4261

Key Words: Pseudomonas aeruginosa; Rhamnolipid; Biosurfactants; Olive oil

Abstract: Rhamnolipids (RLs) represent a very promising class of biosurfactants that have many applications as biocompatible and biodegradable emulsifiers. We have isolated a Pseudomonas aeruginosa strain, denoted strain M408, from petroleum-contaminated soil of the Liaohe oil field (northern China) that is able to produce RLs with a high specificity when grown on olive oil as the sole carbon source. Product analysis of these RLs showed that only di-RLs (F1 sample), including rhamnose (Rha)-Rha-C10-C10 and Rha-Rha-C10-C12/Rha-Rha-C12-C10, and a single mono-RL (F2 sample) of Rha-C10-C10 were produced by the isolate. Further testing revealed that these F1 and F2 products were able to reduce the surface tension of water to 31 and 27 mN/m, respectively. The critical micelle concentration was 120 and 60 mg/L for the F1 and F2 products, respectively. The F1 and F2 products also showed good emulsion stability, achieving an emulsion capacity of 87 and 90 %, respectively, with atoleine after 24 h at a low concentration of 100 mg/L. Maximum production of the RLs was obtained after optimization of the culture conditions, with a 6.85-fold increase in the yield of the RLs, up to 12.6 g/L, relative to the yield before optimization.