Optimisation of biosurfactants produced by non-pathogenic bacteria from environmental samples

Biosurfactants refers to surfactants that can be synthesized by several identified microorganisms including bacteria, yeast and fungi. Majority of the surfactants used in the industries today are manufactured from petro-chemical resources and are known as synthetic/chemical surfactants. These compounds are not only partially biodegradable but are also toxic to living organisms and have contributed to a wide range of environmental hazards/health risks. The development of biosurfactants as potential alternatives to synthetic ones, has recently gained world-wide scientific and industrial attention as interesting classes of compounds because of their outstanding characteristics such as; low toxicity, biodegradability, effectiveness at extreme pH, temperature, alkalinity/acidity and ionic strength, effectiveness at low concentration, excellent emulsification/solubilisation activity, can be synthesised by renewable/waste substrates and have the ability to act as antimicrobial as well as anticancer treating agents. However, due to certain technical and economic factors which one of them includes; the pathogenicity of biosurfactant-producing strains, the industrial scale production and application of biosurfactants is still an unachieved task. This research has been designed to identify new/safe non-pathogenic biosurfactant producing bacteria and to improve their rate of biosurfactant production with the aim of introducing them as biological factories and their biosurfactants can be alternative raw materials in the production of household and health care products. A total of 45 bacterial isolates obtained from two oil-contaminated mangrove soil samples collected from Nigeria, have been screened so far for their ability to produce biosurfactants. Screening for biosurfactant production was done in three selected cultivation media; nutrient broth, mineral salt medium+2% glucose and nutrient broth+3% glycerol and positive results were verified by measuring the reduction in surface tension of cell-free culture supernatant using the Du-Noug ring method. Out of the 45 isolates, 12 have turned out as positive biosurfactant producers. The future plans of the research would include; molecular identification of the positive isolates, improving their rate of biosurfactant production using wastes materials like animal fat and glycerol, characterisation of the biosurfactant produced and to determine their cytotoxicity, antimicrobial, anticancer and emulsification properties. The successful identification of safe biosurfactant- producing microbial strains with the ability to produce sufficient amount of surfactant could create a huge opportunity of replacing the synthetic surfactants with the better biosurfactants in all applicable industrial processes.