One of the major environmental problems today is hydrocarbon contamination resulting from the activities related to the petrochemical industry. Accidental releases of petroleum products are of particular concern in the environment. Hydrocarbon components have been known to belong to the family of carcinogens and neurotoxic organic pollutants. Currently accepted disposal methods of incineration or burial insecure landfills can become prohibitively expensive when amounts of contaminants are large. Mechanical and chemical methods generally used to remove hydrocarbons from contaminated sites have limited effectiveness and can be expensive. Bioremediation is the promising technology for the treatment of these contaminated sites since it is cost-effective and will lead to complete mineralization. Bioremediation functions basically on biodegradation, which may refer to complete mineralization of organic contaminants into carbon dioxide, water, inorganic compounds, and cell protein or transformation of complex organic contaminants to other simpler organic compounds by biological agents like microorganisms. Many indigenous microorganisms in water and soil are capable of degrading hydrocarbon contaminants. This paper presents an updated overview of petroleum hydrocarbon degradation by microorganisms under different ecosystems.

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Microbial Degradation of Petroleum Hydrocarbon Contaminants: An Overview

Environmental applications for biosurfactants

https://www.sbmicrobiologia.org.br/PDF/industrial.pdf

Glycerol: A promising and abundant carbon source for industrial microbiology

Increasing public awareness of environmental pollution influences the search and development of technologies that help in clean up of organic and inorganic contaminants such as hydrocarbons and metals. An alternative and eco-friendly method of remediation technology of environments contaminated with these pollutants is the use of biosurfactants and biosurfactant-producing microorganisms. The diversity of biosurfactants makes them an attractive group of compounds for potential use in a wide variety of industrial and biotechnological applications. The purpose of this review is to provide a comprehensive overview of advances in the applications of biosurfactants and biosurfactant-producing microorganisms in hydrocarbon and metal remediation technologies.

https://www.mdpi.com/1422-0067/12/1/633/pdf

Environmental applications of biosurfactants: Recent advances

Bioremediation approaches for organic pollutants: a critical perspective

https://research.tees.ac.uk/ws/files/6478064/58339.pdf

Enhanced bioremediation of n-alkane in petroleum sludge using bacterial consortium amended with rhamnolipid and micronutrients

https://research.tees.ac.uk/ws/files/6478058/58337.pdf

Towards efficient crude oil degradation by a mixed bacterial consortium.

This study was aimed at the development of economical methods for higher yields of biosurfactant by suggesting the use of low-cost raw materials. Two oil-degrading strains, Pseudomonas aeruginosa GS9-119 and DS10-129, were used to optimize a substrate for maximum rhamnolipid production. Among the two strains, the latter produced maxima of 4.31, 2.98, and 1.77 g/L rhamnolipid biosurfactant using soybean oil, safflower oil, and glycerol, respectively. The yield of biosurfactant steadily increased even after the bacterial cultures reached the stationary phase of growth. Characterization of rhamnolipids using mass spectrometry revealed the presence of dirhamnolipids (Rha-Rha-C(10)-C(10)). Emulsification activity of the rhamnolipid biosurfactant produced by P. aeruginosa DS10-129 was greater than 70% using all the hydrocarbons tested, including xylene, benzene, hexane, crude oil, kerosene, gasoline, and diesel. P. aeruginosa GS9-119 emulsified only hexane and kerosene to that level.

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Rhamnolipid biosurfactant production by strains of Pseudomonas aeruginosa using low-cost raw materials.

https://research.tees.ac.uk/ws/files/6478030/58336.pdf

Bioremediation of gasoline contaminated soil by a bacterial consortium amended with poultry litter, coir pith and rhamnolipid biosurfactant.

A study was undertaken to investigate the distribution of biosurfactant producing and crude oil degrading bacteria in the oil contaminated environment. This research revealed that hydrocarbon contaminated sites are the potent sources for oil degraders. Among 32 oil degrading bacteria isolated from ten different oil contaminated sites of gasoline and diesel fuel stations, 80% exhibited biosurfactant production. The quantity and emulsification activity of the biosurfactants varied. Pseudomonas sp. DS10-129 produced a maximum of 7.5 +/- 0.4 g/l of biosurfactant with a corresponding reduction in surface tension from 68 mN/m to 29.4 +/- 0.7 mN/m at 84 h incubation. The isolates Micrococcus sp. GS2-22, Bacillus sp. DS6-86, Corynebacterium sp. GS5-66, Flavobacterium sp. DS5-73, Pseudomonas sp. DS10-129, Pseudomonas sp. DS9-119 and Acinetobacter sp. DS5-74 emulsified xylene, benzene, n-hexane, Bombay High crude oil, kerosene, gasoline, diesel fuel and olive oil. The first five of the above isolates had the highest emulsification activity and crude oil degradation ability and were selected for the preparation of a mixed bacterial consortium, which was also an efficient biosurfactant producing oil emulsifying and degrading culture. During this study, biosurfactant production and emulsification activity were detected in Moraxella sp., Flavobacterium sp. and in a mixed bacterial consortium, which have not been reported before.

/pdf/the-potential-of-bacterial-isolates-for-emulsification-with-3zupvnjg8w.pdf

K. S. M. Rahman

Papers

Enhanced bioremediation of n-alkane in petroleum sludge using bacterial consortium amended with rhamnolipid and micronutrients

Towards efficient crude oil degradation by a mixed bacterial consortium.

Rhamnolipid biosurfactant production by strains of Pseudomonas aeruginosa using low-cost raw materials.

Bioremediation of gasoline contaminated soil by a bacterial consortium amended with poultry litter, coir pith and rhamnolipid biosurfactant.

The potential of bacterial isolates for emulsification with a range of hydrocarbons