title: Production of rhamnolipids by Pseudomonas aeruginosa is inhibited by H2S but resumes in a co-culture with P. stutzeri: applications for microbial enhanced oil recovery.
abstract: OBJECTIVE
  Sulfate-reducing bacteria and H2S exist widely in oil production systems, and in situ production of rhamnolipids is promising for microbial enhanced oil recovery (MEOR). However, information of the effect of S(2-) on rhamnolipids production is scarce.
  
  
  RESULTS
  Two facultative anaerobic rhamnolipids-producing bacterial strains, Pseudomonas aeruginosa SG and WJ-1, were used. Above 10 mg S(2-)/l, both cell growth and rhamnolipids production were inhibited. A large inoculum (9%, v/v) failed to completely relieve the inhibitory effect of 10 mg S(2-)/l. Below 30 mg S(2-)/l, both strains resumed rhamnolipid production through co-culturing with the denitrifying and sulphide-removing strain Pseudomonas stutzeri DQ1.
  
  
  CONCLUSIONS
  H2S has a direct but reversible inhibitory effect on rhamnolipids production. Control of H2S in oilfields is indispensable to MEOR, and the co-culture method is effective in restoring rhamnolipid production in presence of S(2-).
authors.affiliation: Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, People's Republic of China, zhao2008569@126.com.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhao
authors.forename: Fang
authors.initials: F
authors.lastname: Ma
authors.forename: Rongjiu
authors.initials: R
authors.lastname: Shi
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Siqin
authors.initials: S
authors.lastname: Han
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D018920:Coculture Techniques; D006017:Glycolipids / Q000096:biosynthesis*; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D061329:Oil and Gas Fields / Q000737:chemistry; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D044223:Pseudomonas stutzeri / Q000254:growth & development*
chemical_list: D006017:Glycolipids; C418382:rhamnolipid; D006862:Hydrogen Sulfide