A Pesticide Biopurification System: A Source of Biosurfactant-Producing Bacteria with Environmental Biotechnology Applications

Abstract

Biosurfactants, a wide group of compounds produced by different microorganisms, generally have less toxicity and are more biodegradable than synthetic surfactants. Biosurfactant-producing bacteria can be found in contaminated environments, such as soils receiving pesticide applications constantly, or in pesticides treatment systems where microorganisms are adapted to biodegrading pesticides. Five pesticide-tolerant bacteria previously isolated from a pesticide biopurification system were evaluated as biosurfactant-producers. Pseudomonas rhodesiae C4, Rhodococcus jialingiae C8 and Pseudomonas marginalis C9 strains were positive in qualitative tests. Biosurfactant production by these strains using Bushnell-Haas medium with olive oil at 2% (w/v) was evaluated as emulsification index, oil displacement, droplet collapse test and surface tension. After 144 h, these strains showed a similar emulsification index of >55%. The two Pseudomonas (C4 and C9) strains showed lower superficial tension compared with Rhodococcus strain (C8)—34.47, 37.44 and 47.55 mN/m for strains C4, C9 and C8, respectively. The chemical characterization of the biosurfactants revealed the presence of glycolipids in P. rhodesiae (C4) and glycopeptides in P. marginalis (C9). The degradation of chlorpyrifos increased from 39.2% to 51.6% when biosurfactants produced by P.rhodesiae (C4) were added (10%) with respect to the control. Therefore, biopurification systems are a relevant source of biosurfactant-producing bacteria with environmental biotechnology applications.

Tapping the Role of Microbial Biosurfactants in Pesticide Remediation: An Eco-Friendly Approach for Environmental Sustainability

“…Pesticides are the chemical compounds used to kill unwanted pests such as bugs, flies, rodents, nematodes, fungal pathogens, and unwanted herbs to maintain plant health and increase agricultural production on limited land. Pesticides play an essential part in fulfilling the world food demand, though they are very hazardous, persistent, recalcitrant, and have extended half-life properties ( Wattanaphon et al, 2008 ; Damalas and Eleftherohorinos, 2011 ; Odukkathil and Vasudevan, 2016 ; Lamilla et al, 2021 ). The most common pesticides used in India and the other countries are organophosphates like chlorpyrifos, profenofos, and glyphosate, with a few being organochlorine i.e., mirex, lindane, and chlordane ( Lamilla et al, 2021 ).…”

“…Pesticides play an essential part in fulfilling the world food demand, though they are very hazardous, persistent, recalcitrant, and have extended half-life properties ( Wattanaphon et al, 2008 ; Damalas and Eleftherohorinos, 2011 ; Odukkathil and Vasudevan, 2016 ; Lamilla et al, 2021 ). The most common pesticides used in India and the other countries are organophosphates like chlorpyrifos, profenofos, and glyphosate, with a few being organochlorine i.e., mirex, lindane, and chlordane ( Lamilla et al, 2021 ). These organophosphorus and organochlorine pesticides are not target-specific and have high biological stability in the soil and water bodies, polluting the ecosystem and making it pestilent for humans and other organisms such as pollinators, cattle, microbes, and aquatic organisms ( Gennari et al, 2009 ; Sequinatto et al, 2013 ).…”

“…Researchers worldwide are now trying to create the most cost-effective and long-term sustainable method for pesticide bioremediation. Microbial biosurfactant-based remediation is a natural, cost-effective, and environmental friendly method of on-site degradation of pesticides and other xenobiotics in which biosurfactants make pesticides bioavailable and microbes use them as a source of carbon, nitrogen, and phosphorous ( Abouseoud et al, 2008 ; Luna et al, 2013 ; Chaprão et al, 2015 ; Odukkathil and Vasudevan, 2016 ; Bhatt et al, 2021b ; Lamilla et al, 2021 ).…”

“…Biosurfactants are secondary metabolites produced by microorganisms used in many commercial applications due to their low toxicity, substantial biodegradability, and environmentally benign nature ( Thavasi et al, 2011 ; Chaprão et al, 2015 ; Javee et al, 2020 ). Biosurfactants consist of both hydrophilic and hydrophobic regions that are formed from amino acids, as well as saturated and unsaturated fatty acids, respectively ( Sharma et al, 2015 ; Bhatt et al, 2021b ), which enables a reduction in surface tension and reaching out between two solvate molecules, thus accelerates the solvation of hydrophobic molecules in aqueous media for emulsion formation ( Banat, 1995 ; Lamilla et al, 2021 ). It has been observed that hydrocarbon-contaminated areas are the best places to isolate biosurfactant-producing microorganisms to improve pesticide remediation ( Singh et al, 2016 ; Tan and Li, 2018 ; Bhatt et al, 2021a ; Lamilla et al, 2021 ).…”

Production optimization, stability and oil emulsifying potential of biosurfactants from selected bacteria isolated from oil-contaminated sites

“…The chemical nature of the partially purified biosurfactants was determined by various biochemical examinations. Ninhydrin test was performed as reported by Feignier et al[35], biuret test was performed according to Patowary et al[36], Molisch's test was performed according to the method of Vanavil et al[37] and thin layer chromatography according to Lamilla et al[38].royalsocietypublishing.org/journal/rsos R. Soc. Open Sci.…”