A novel Serratia sp. ZS6 isolate derived from petroleum sludge secretes biosurfactant and lipase in medium with olive oil as sole carbon source

Xingcui Hu,Tao Cheng,Jianhua Liu

doi:10.1186/s13568-018-0698-9

Abstract

Biosurfactants emulsify lipids, facilitating their exposure to microorganisms in water. Secretion of biosurfactant together with lipase can enhance oil assimilation by microorganisms. In this study, we show the analysis of the biosurfactant and lipase producing microbe originating from oil-sludge. The enrichment of the biosurfactant-producing ZS6 strain from the mixed culture of sludge-derived microbes in medium with olive oil as sole carbon source was monitored using the modified T-RFLP (or mT-RFLP) methodology. Phylogenetic tree analysis based on 16S rDNA sequences suggested that ZS6 belonged to a member of Serratia sp. Serratia sp. ZS6 secreted both a serrawettin-type biosurfactant and lipase in medium with olive oil as sole carbon source. By using an in-gel lipase assay followed by LC–MS/MS analysis, we identified the amino acid sequences of the ZS6 lipase, which belonged to the lipase subfamily III of the family I. Its lipolytic activity was found to be enhanced by salinity, calcium, and methanol. Together, we show that the novel isolate Serratia sp. ZS6 secretes both biosurfactant and lipase which makes it useful for applications such as in food industry wastewater treatment and biodiesel production.

Highlights

Biosurfactants are amphiphilic molecules such as fatty acids (Cooper et al 1981; Knickerbocker et al 2000), lipopeptides (Matsuyama et al 1992; Seydlova and Svobodova 2008), glycolipids (Reiling et al 1986; Van Bogaert et al 2007), siderophore (Bodour et al 2004; Rosenberg and Ron 1997), etc. that are present in plants and animals as well as microorganisms
Isolation of biosurfactant‐producing microbes in medium with olive oil as sole carbon source We wanted to investigate whether microorganisms derived from petroleum sludge would grow in mineral salt (MS) medium supplemented with 2% olive oil as sole carbon source
We concluded that biosurfactant-producing microbes were enriched in culture 60 h after growth in MS medium supplemented with olive oil

Summary

Introduction

Biosurfactants are amphiphilic molecules such as fatty acids (Cooper et al 1981; Knickerbocker et al 2000), lipopeptides (Matsuyama et al 1992; Seydlova and Svobodova 2008), glycolipids (Reiling et al 1986; Van Bogaert et al 2007), siderophore (Bodour et al 2004; Rosenberg and Ron 1997), etc. that are present in plants and animals as well as microorganisms. Biosurfactants are amphiphilic molecules such as fatty acids (Cooper et al 1981; Knickerbocker et al 2000), lipopeptides (Matsuyama et al 1992; Seydlova and Svobodova 2008), glycolipids (Reiling et al 1986; Van Bogaert et al 2007), siderophore (Bodour et al 2004; Rosenberg and Ron 1997), etc. That are present in plants and animals as well as microorganisms. Biosurfactants produced by microorganisms have attracted much attention for their diversity, performance under extreme conditions, possibility of large-scale production (Banat et al 2000; Rahman et al 2002)

Methods

Results

Conclusion