Production of biosurfactant by heavy-metal resistant native isolate

Background and Aim : Petroleum-based fuels are prominent pollutants in the most countries. While surfactants enhance recovery of crude oil, their toxicity and carcinogenicity are problematic. Besides, attention to microbial surfactants is increasing. Biosurfactants (BS) or bioemulsifiers are pioneer groups of valuable natural microbial compounds with unique features. However, studies typically using isolated microorganisms from different sites for biodegradation of oil pollutions but there is possibility to presence of bacteria with high biodegradation ability from uncontaminated environments.Methods : With attention to increasing demand for microbial biosurfactants, this study aimed to screening of biosurfactant-producing bacteria from previous heavy-metal resistant isolates. For this, at the first stage, some qualitative assay such as haemolytic activity (HA) was used for screening. Other assays which were applied including oil-displacement test (for efficiency of produced biosurfactant); emulsification index (EI) (for BS stability) and cellular surface hydrophobicity (BATH). The identification and further studies are being doing.Results : The screening results showed that one isolate (CBS-۸C) has the potential of HA as an indicative for biosurfactant production. In the following step, CBS-۸C isolate showed EI equal to ۶۰ in minimal salt medium (MSM) with crude oil.Conclusion : In recent years, with attention to biosurfactants applications in different industries, their production has been studied. Biosurfactant-producing microorganisms are ubiquitous in waters, land and extreme environments. With reference to gathered results, it could be said that with further studies for produced biosufractant characterization and with enhancement of its production, this strain could be used especially with its heavy-metal resistant ability.

کلیدواژه ها:

biosurfactant ، heavy metal ، native ، petroleum