Soil pollution and land degradation are global problems originating from anthropological and natural sources (Malla et al., 2018). Urbanization and industrialization are the major sources of anthropological pollution while the use of chemical agents over the year for increasing crop production has led to the spread and accumulation of pollutants in the environment (Prihandiani et al., 2021). The most common contaminants in the soil are heavy metals, polycyclic aromatic hydrocarbons (PAHs), or pesticides. 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). 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). Most organophosphate pesticides are classified as class II carcinogens with mutagenic, teratogenic, and carcinogenic effects on humans and other organisms (Bhatt et al., 2021a).

Looking at the grave danger of these toxic pollutants, there is an urgent need to deal with the harmful impacts of these toxic pesticides. Most physical and chemical pesticide removal methods have been in use for a long time. These methods include aeration, oxidation, excavation, incineration, landfilling, and storage, etc., which is labor-intensive, time-consuming, inefficient, and are not considered a sustainable method of remediation because they result in the generation of several secondary pollutants (Yoshikawa et al., 2017; Bhatt et al., 2021a). As a result, the implementation of bioremediation appears as the only answer to the issue mentioned above since it uses the ability of live indigenous microorganisms to clean the polluted site (Singh et al., 2011). 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). Figure 1 depicted the entry of pesticides into the food chain and the fate of pesticides and presented the mechanism of biosurfactant mediated pesticides degradation. Several published reports are available wherein biosurfactant producing potential of microbes have been utilized for bioremediation of pesticides.

Although most of the studies on bioremediation are done using single microbes (particularly culturable ones). Several reports suggest the microbial consortia enhances the remediation process compared to a single isolate (Pacwa-Płociniczak et al., 2011; Rasheed et al., 2020; Madamwar et al., 2021). While in several cases, the role of unculturable microbes is often ignored, and the underlying mechanism of microbes-mediated pesticides degradation is still unexplored (Singh and Gupta, 2018; Singh et al., 2019). The use of metagenomics to understand the underlying mechanisms of biodegradation in in-situ and to forecast degradation potential has yet to be studied. So, there is a lack of information about microbes’ functional genes and genetic potential and their products like biosurfactants involved in degradation (Datta et al., 2020; Femina Carolin et al., 2020). Against this background, this article aims to give a comprehensive overview of the function of microbial biosurfactants in the remediation of pesticides. We also briefly addressed how improved metagenomics techniques might assist clean-up by providing access to uncultivable microbial species.

The tremendous demand to produce food at reasonable prices has forced farmers/growers to use chemical fertilizers and pesticides (Sarath Chandran et al., 2019). Organochlorine pesticides such as DDT (dichlorodiphenyltrichloroethane) and Gammaxene were used extensively during the second world war, but they proved to be an ecological disaster for the world and was banned by the United States in 1972 due to their toxic effects on the peripheral nervous system and its non-biodegradable nature. Several developed and developing nations banned the use of most organochlorine pesticides, including DDT (Mansouri et al., 2017; Peng et al., 2020). This led to increased demand for organophosphate pesticides such as malathion, parathion, monocrotophos, etc., due to their wide action spectrum and moderate toxicity (Narenderan et al., 2020; Parks et al., 2021). However, feeding the exponentially growing population on declining land area forced farmers to use these pesticides more than the recommended dose i.e., 1 U.S liquid pints per acre of land or 0.473 liters per acre of land area (Tchounwou et al., 2015; As per U.S. Environmental Protection Agency | US EPA, 2021). Insecticides, herbicides, rodenticides, and fungicides are among the most regularly used pesticides (Malla et al., 2018) and were used excessively during the green revolution to increase productivity and reduce crop loss (Sarath Chandran et al., 2019). Pesticide use is rising and negatively influencing the environment, particularly the soil quality and health (Rawat et al., 2020), as only 1% of sprayed pesticides kill target species; the rest pollute the ecosystem by interacting with soil and generating more complex metabolites. For example, chlorpyrifos produces 3,5,6-trichloro-2-pyridinon (TCP), an antimicrobial metabolite that kills beneficial soil microorganisms and due to its eco-toxicity, the United nation banned this pesticide in the year 2020. However, chlorpyrifos is extensively used in developing countries like India, Bangladesh, and Pakistan (John and Shaike, 2015; Shabbir et al., 2018; Kalyani et al., 2021). Pesticides strongly adsorb the soil’s organic matter, which restricts its desorption. Most of the pesticides are non-polar compounds having hydrophobic properties and are insoluble in water (Bhatt et al., 2021b; Kalyani et al., 2021). Pesticides are highly recalcitrant on exposure to humans; they lead to several disorders related to the central nervous system as most of these chemicals inhibit acetylcholinesterase receptor activity, causing nerve damage. Apart from it, inhalation of pesticides leads to several respiratory disorders and these chemicals also have mutagenic and carcinogenic potential causing disorders related to fertility, excretory system, skin, and eye defects (Figure 1; Foong et al., 2020; Giri et al., 2020). According to reports on poisoning and the impact of synthetic chemicals on human health, numerous cases of intoxication of farmers, rural workers, and their families have occurred during pesticide applications. Unintentional poisonings kill an estimated 3,55,000 people annually and are related to excessive exposure and improper use of hazardous substances (Nayak et al., 2020).

Biosurfactants which are surface-active molecules produced naturally by microbial metabolism have gained popularity in recent times. In recent years, there has been a steady increase in the number of research papers focused on the isolation, characterization, and optimization of biosurfactants producing microbes (Das and Kumar, 2018; Olasanmi and Thring, 2018; Khanna and Pattnaik, 2019; Rawat et al., 2020). Biosurfactants are the type of “glycoconjugates (combination of glycoprotein and glycolipids),” and the study of its structure, function, and interaction with the living system is called “glycobiotechnology” (Messner et al., 2013; Enaime et al., 2019). Microbes produce some extracellular biosurfactants such as rhamnolipids, sophorolipids and exopeptidases, and glycol-lipopeptides. A wide variety of anionic and non-ionic synthetic surfactants (Triton X-100, tween-80, tergitol NP10, brij35, sodium dodecyl sulfate etc.) are in use for a long time to accelerate microbial activity whether in the area of xenobiotic remediation or biofuel production (da Rocha et al., 2010).

Furthermore, they are extensively used by pesticide industries as an emulsifiable concentrate in the pesticide formulation. However, synthetic surfactants are highly toxic, non-biodegradable, have low selectivity, high CMC value, and show antimicrobial activity (Bustamante et al., 2012; Yañez-Ocampo et al., 2017). Therefore, another reason for the popularity of biosurfactants is their advantages over their chemically manufactured counterparts, such as having a simpler structure than the synthetic equivalents, being environmentally friendly, and lesser toxicity (Rawat et al., 2020). On the other hand, biosurfactants can survive up to 10% salinity, but synthetic surfactants cannot. Other than their essential role in pesticide remediation (Tan and Li, 2018), they are also used in various commercial products, including medications, cosmetics, cleaning agents, and the food sector (Santos et al., 2016).

Most microbes produced biosurfactants on their cell surface (amphiphilic molecules) as secondary metabolites at their stationary phase of growth (Soberón-Chávez et al., 2005; Moya Ramírez et al., 2015). These biosurfactants include glycoproteins, glycolipids, glycopeptides, glycosides, peptidoglycan, and lipopolysaccharides, which are the diverse forms of glycoconjugate-based biosurfactants (Varjani and Upasani, 2016; Bhatt et al., 2021b). One of the distinguishing features of biosurfactants is the hydrophilic-lipophilic balance (HLB), which determines the proportion of hydrophilic and hydrophobic elements in surface-active substances (Pacwa-Płociniczak et al., 2011). Biosurfactant activities are dependent on the concentration of surface-active molecules till the critical micelle concentration (CMC) is attained. Biosurfactant compounds form micelles, bilayers and vesicles at a concentration above CMC (Rasheed et al., 2020) and these micelles can reduce surface and interfacial tension and increase the solubility and bioavailability of hydrophobic pesticide molecules (Bhatt et al., 2021b). Surfactant efficiency is frequently measured using the CMC, as efficient biosurfactants have a low CMC, and require less biosurfactant to reduce surface tension (Pacwa-Płociniczak et al., 2011; Bhatt et al., 2021a,b). Micro-organisms may synthesize biosurfactants from various carbon sources, but Glycine max, Zea mays, Brassica napus, and Olea europaea can be employed to increase output (Bhatt et al., 2021b). Many researchers have tried producing biosurfactants from unconventional and agricultural-based raw materials; however, this approach has not yet been commercialized. These lipopeptides may be made from low-cost raw materials such as Saccharum officinarum, Zea mays, molasses, agricultural wastes, and others that are easily accessible in large numbers to be cost-effective (Hippolyte et al., 2018; Domínguez Rivera et al., 2019; Rawat et al., 2020). The structure and composition of the biosurfactant molecule and the role of biosurfactants in pesticide remediation is shown in Figures 3, 4.

Pesticide contamination is a significant problem. The use of biosurfactants for pesticide biodegradation has recently gained popularity. According to ZION market research and global market insights, the worldwide biosurfactant industry is projected to reach $2.4 billion by 2025 (Lai et al., 2009; Sun et al., 2015). The biosurfactant market is anticipated to grow as the pesticide business grows and consumers become more health-conscious (Rawat et al., 2020). The most crucial role that biosurfactants play is the dissociation of toxic pesticide molecules from the soil or water molecules, thus making it bioavailable for the microbes to speed up the remediation process (Figure 5; Inakollu et al., 2004; Whang et al., 2009; Rasheed et al., 2020). Desorption from soil particles leads to a reduction in surface tension, thus enhancing the mechanism of degradation (Singh et al., 2007; Twigg et al., 2019). The probable interaction used for pesticides bioremediation by biosurfactants includes electrostatic interactions, counter-ion binding, ion exchange, and precipitation-dissolution (Banat et al., 2010; Patowary et al., 2017; Xu et al., 2018).

Biosurfactants enhance the surface area of hydrophobic pesticides, increasing their solubility in soil and water by inducing emulsification of pesticide molecules (Bhatt et al., 2021b). The thumb rule of bioremediation is that the more the amount of pesticide that is water-soluble, the greater the amount of pesticide bioavailable to microorganisms. Surface-active apolar flocculating molecules such as biosurfactants, which produce emulsions at and above their critical micellar concentration, may enhance the separation of hydrophobic pesticides from the aqueous phase by creating emulsions at and above their critical micellar concentration (CMC). When pesticides are released into the environment, they become more bioavailable to possible degraders, which may help alleviate the worry about pesticide contamination of soil and water bodies (Zhou et al., 2011; Moya Ramírez et al., 2015). As a result, the soil becomes free of pollutants, productive, and suitable for crop cultivation (Fenibo et al., 2019; Jimoh and Lin, 2019a). The overall mechanism of soil, microbes and pesticide interaction is shown in Figure 5.

Rhamnolipids are the most widely used biosurfactants in industrial and environmental clean-up applications. The potential of rhamnolipid in bioremediation has been extensively studied in Pseudomonas and Burkholderia species (Varjani and Upasani, 2016). Rhamnolipids obtained from Pseudomonas aeruginosa enhance biodegradation of herbicide trifluralin and insecticide chlorpyrifos in the contaminated soil-water bodies (Singh et al., 2016; Tan and Li, 2018). It has been reported that the presence of glycolipid type of biosurfactant obtained from Pseudomonas species enhances solubilization of methyl parathion and endosulfan (García-Reyes et al., 2018). With around 100 gL^–1, Pseudomonas aeruginosa is regarded as the top rhamnolipid producer and it produces two forms of rhamnolipids in liquid suspension i.e., mono and di-rhamnolipid (Varjani and Upasani, 2016) by rhamnosyl transfer enzymatic reaction with the help of rhamnosyltransferase enzyme (Soberón-Chávez et al., 2005; Varjani and Upasani, 2017). The hydrophobic and hydrophilic components of the rhamnolipid are formed due to a series of enzymatic processes that take place in microbes. After synthesis, the two halves of the lipid are linked together to form mono- and di-rhamnolipids, respectively (Bhatt et al., 2019). A rhamnolipid was formed from an axenic culture of Pseudomonas putida strain DOT-T1E, which aided in the bioremediation of chlorinated phenols (Maia et al., 2019). The trapping of the chlorophenol in the biosurfactant micelles, as well as the hydrophobic connection between these two types of molecules, are at the heart of this action. Likewise, actinobacteria-formed biosurfactant accelerates the bioremediation of xenobiotics (Sponza and Gok, 2011). In the bioremediation of carbendazim with Rhodococcus species D-1, rhamnolipids were found efficient. With the highest bioremediation efficiency, the rhamnolipid altered carbendazim degradation in a concentration-dependent manner. It aided carbendazim transesterification and favorable cell surface modification, allowing it to enter Rhodococcus species D-1 cells, which were degraded (Bai et al., 2017). Glucolipid type of biosurfactant produced by Burkholderia cenocepacia BSP3 complements the solubilization of pesticide (Bustamante et al., 2012). Biosurfactants that spontaneously break down the pesticides are good for the environment and are considered environmentally benign (Jezierska et al., 2019).

Rhizospheric bacteria’s have been reported to play a key role in the degradation of pesticides, accelerating the breakdown as seen during biosurfactant biosynthesis (Bordoloi and Konwar, 2009; Singh, 2015; Dos Santos and Maranho, 2018). The amount of biosurfactant is also vital for microbial development. High quantities of these biosurfactants inhibit microbial growth and breakdown. These findings may not apply to all microbial strains. A study shows that biosurfactant addition increased 30% endosulfan degradation with the help of Bacillus subtilis MTCC 1427 in the soil and aqueous solution (Zhou et al., 2011). Endosulfan isomers were found to have more significant mobilization and accessibility in the presence of biosurfactant, which could be due to pesticide solubilization or improved attraction for micro-organism cells. Due to the formation of rhamnolipids by P. aeruginosa, the soil adulterated with endosulfan showed accelerated degradation after 7 days of the experiment (Madamwar et al., 2021). The published article indicated that the Pseudomonas strain BO406 produced a raw extract of a biosurfactant (glycolipid) that aided in the solubilization of endosulfan (García-Reyes et al., 2018). The strain of Lysinibacillus sphaericus IITR51 was used by researchers to develop a thermostable rhamnolipid biosurfactant capable of increasing the solubility of the highly hydrophobic pesticides such as endosulfan and HCH (hexachlorocyclohexane) (Manickam et al., 2012; Gaur et al., 2019). A strain of Pseudomonas SB can produce a biosurfactant that enhances DDT breakdown. Rhamnolipid has been reported to increase DDT degradation by 64% from 52% without rhamnolipid (Bhatt et al., 2021b). Studies on mixed consortia of Pleurotus ostreatus (white-rot fungus), Bacillus subtilis, and P. aeruginosa have produced biosurfactants that improve DDT biodegradation (Purnomo et al., 2017; Bhatt et al., 2021b). The hydrophobic herbicide 2,4,5-trichlorophenoxy acetic acid was degraded with the help of a biosurfactant produced from Pseudomonas cepacian (Abdul Salam and Das, 2013; Pang et al., 2020; Rawat et al., 2020). Similarly, introducing rhamnolipid to Rhodococcus species-D1 resulted in increased carbendazim biodegradation. The addition of rhamnolipid to the soil resulted in around 24–35% biodegradation of trifluralin (Bai et al., 2017). Under atrazine biodegradation, a marine strain of Bacillus velezensis MHNK1 produced surfactin lipopeptide. The atrazine was degraded entirely after using a combination of B. velezensis MHNK1 (2%) and surfactin for 4 days (Jakinala et al., 2019).

A very interesting example of the application of biosurfactant in pesticide remediation is from the Patagonia region, which is famous for salmon farming, and to protect salmons from parasitic attack, cypermethrin (A pyrethroid category of pesticide) is used extensively in marine water. Scientists isolated microbial strains Rhodococcus species MS13, Rhodococcus species MS16, Pseudomonas species MS15a, and Pseudomonas species MS19 that could degrade cypermethrin by the production of biosurfactant (Aguila-Torres et al., 2020). A novel strain of Serratia species Tan 611 has been isolated from Algeria’s oil-contaminated waste-water. Its further sequencing and annotation revealed that it consists of genes that code for catechol 1,2-dioxygenase and naphthalene 1,2-dioxygenase, which are primarily responsible for aromatic derived hydrocarbon catabolism (Clements et al., 2019). An alkane degrading gene Lad-A that codes for monooxygenase have also been identified in the same strain. The bacterially produced biosurfactant has an emulsification index of about 43.47–65.22% and forms biofilms in the presence of oil spills and petroleum. Further studies revealed that Serratia species strain Tan611 proves to be one of the best candidates in microbial remediation of aromatic pesticides (Semai et al., 2021). Biosurfactants boost the rate of pesticide degradation when a microbial consortium is used for bioremediation due to the synergistic influence of microbial communities (Purnomo et al., 2017; Bhatt et al., 2019; Femina Carolin et al., 2020).

Metagenomics analysis based on the sequence and function of the unculturable microbial community will help to uncover information in different ecological niches (Dubey et al., 2019; Kumar et al., 2019; Malla et al., 2019; Kumar and Dubey, 2020). The finding of novel microorganisms or their gene clusters expressing biosurfactants is an example of its application (Datta et al., 2020). Metagenomics provides access to the uncultured microbial population along with their taxonomic and functional composition based on targeted or shotgun sequencing of 16S rRNA regions (Datta et al., 2020). The function-based approach detects and discovers genes capable of forming wholly new bioactive compounds that have never been identified before (Shikha et al., 2021). From pesticide-contaminated materials (soil, water), metagenomics helped create DNA libraries tested for biosurfactant-producing clones. There are many techniques for screening metagenomic libraries for biosurfactants, including function-based approaches like SIGEX (substrate-induced gene expression) and HTP (high-throughput) screening (Datta et al., 2020; Femina Carolin et al., 2020). The investigation of microbial metagenomes can also help researchers to gain a better knowledge of microbes that can produce biosurfactants in a variety of environments, particularly pesticides contaminated soils (Shikha et al., 2021).

The use of function-based metagenomic strategies can be a potent tool in helping to exploit the unique microbial diversity of pesticide-contaminated environments, thereby assisting in the ongoing search for novel biosurfactants with potentially important bioremediation applications (Yadav et al., 2019; Taş et al., 2021). Most research on biosurfactant producing microbes has been limited to soil isolates, primarily from the Pseudomonas and Bacillus species. However, with the help of metagenomics, it has recently been discovered that a diverse group of soil and marine microbes can produce biosurfactants (Dhanjal and Sharma, 2018; Guerra et al., 2018; Garg et al., 2021) and some of these biosurfactants have shown potential in bioremediation of pesticides (Kennedy et al., 2011; Ghosh and Das, 2018). These microbes include Azotobacter chroococcum, Cobelia species, Myroides species, Nocardiopsis alba MSA10, Alcanivorax species, Micrococcus luteus, Yarrowia lipolytica. There is a variety of screening approaches for detecting biosurfactant-producing microbes (as discussed in section “Methods for Detection of Microbial Biosurfactants”), some of which could be used for high-throughput (HTP) metagenomic library screening (Domingos et al., 2015; Dhanjal and Sharma, 2018; Guerra et al., 2018). Thus, in screening, it is likely that novel gene clusters involved in biosurfactant production from soil and aquatic microbial assemblages will be discovered, speeding up the development of bioremediation technologies involving biosurfactants in pesticide-contaminated environments (Hemmat-Jou et al., 2018; Taş et al., 2021). The whole workflow of metagenomics investigation of biosurfactant producing microbes is presented in Figure 6.

Metagenomics assists in the investigation of unique biosurfactant-producing genes from the bacteria present in diverse environments and distinct pathways and approaches for improved biosurfactant production. These investigations helped in finding two novel biosurfactants; palmitoyl putrescine and N-acyl amino acids (Jackson et al., 2015; Williams and Trindade, 2017; Hu et al., 2019; Singh et al., 2020b). Given the amount and diversity of biosurfactant synthesizing microbes found in cultured isolates, it is believed that employing metagenomics to investigate the even larger uncultured component of the microbial community will lead to major novel biosurfactant discoveries (Datta et al., 2020; Singh et al., 2020b). A group of researchers identified a new gene involved in biosurfactant synthesis and helps in hydrocarbon degradation. They named it MBSP1 (Carla da Silva Araújo et al., 2020) (metagenomic biosurfactant protein 1) (Araújo et al., 2020). Thies et al. (2016) conducted a metagenomic study by collecting samples from the drain of the slaughterhouse that was rich in microbes belonging to flavobacteriaceae and, through NMR-spectroscopy identified novel biosurfactant as N-acyltyrosines along with N-myristoyl-tyrosine as the dominant species (Thies et al., 2016). Metagenomics delivers an adequate metagenomic database that will give a substantial stock of genes to develop novel microbial strains for targeted application in biosurfactant production and bioremediation (Malla et al., 2018; Datta et al., 2020; Douglas et al., 2020; Kumar et al., 2021b). Metagenomics coupled with bioinformatics removes all the obstacles faced in the process of genomic studies such as phylogenetic analysis, taxonomic profiling, molecular phylogeny, functional characterization of metagenomes, and enzymes and system biology studies, including genetic engineering through CRISPR or TALEN (Singh et al., 2020b). Quite a few bioinformatic pipelines have been developed (Table 2), such as QIIME (quantitative insights into microbial ecology), PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved states), MG-RAST (metagenomic rapid annotations using subsystems technology), Mothur, CLARK, MetaPhlAn2 (metagenomic phylogenetic analysis), MICCA, Metaphyler, MOCAT₂, TIPP2, mOTU_sv2, Bracken, etc., for sequence classification and taxonomic profiling of metagenomic data (Liu et al., 2010; Albanese et al., 2015; Truong et al., 2015; Douglas et al., 2020; Singh et al., 2020b). Metagenomics coupled with in-silico bioinformatic tools or repositories such as KEGG (Kyoto encyclopedia of genes and genomes), COG (clusters of orthologous groups), EAWAG-BBD pathway prediction system, enviPath, BIOWIN, etc., helps in predictive degradation of pesticides along with the metabolite/biosurfactant identification involved in degradation mechanism (Awasthi et al., 2020; Rodríguez et al., 2020; Shah et al., 2021; Singh et al., 2021). A repository named BioSurfDB (biosurfactant degradation database) consists of about 1,077 microbes, 3,763 genes, 3,430 proteins, and 47 detailed bioremediation pathways using biosurfactants (Araújo et al., 2020; Meenatchi et al., 2020; Kumari and Kumar, 2021).

To date, only a few research employing genetic modification methods for biosurfactant production have been published, and one such research is genetic modification of wild Bacillus strain for surfactin production (Tsuge et al., 2001). Bacillus species are engineered to increase their production through operon promoter transfer (SrfA) or upregulation of the exporter (YerP). Due to intricate metabolic regulation and its long genomic sequence, this operon’s production is difficult (Hu et al., 2019; Singh et al., 2020a). However, genetic engineering methods only resulted in a few or single-gene alterations, and commercial manufacturing of biosurfactants has yet to be achieved. As a result, experimentation-based optimizations to synthesize biosurfactants are still ongoing, and a new regulatory aspects need to be investigated, and the latest CRISPR based methods should be used to transfer biosurfactant producing genes to indigenous microbes residing in contaminated sites (Mulligan, 2009; Sekhon et al., 2011; Soares da Silva et al., 2019; Kumar and Dubey, 2020).

Pesticides are complex compounds that are hydrophobic. When used in excess, pesticides pollute the air, soil, and water bodies because they interact with soil particles and leach deep into the soil and water bodies, making them inaccessible for microbial activity to thrive. Microbial biosurfactants serve an essential role in making these pesticides accessible for microbial enzymatic breakdown. Biosurfactants dissolve pesticides linked to soil particles and create emulsions at and above their CMC, thus increasing the bioavailability of the pesticide molecule in the soil. Different microbes secrete different categories of biosurfactants, each of which contributes more or less to enhancing the remediation process. More emphasis should be placed on improving process parameters to maximize the production of biosurfactants and their application in pesticide remediation. Tapping the potential of biosurfactant producing microbes by using the latest omics platform and gene-editing tools may offer a sustainable way to remediate these pesticides from the environment.

Although, research is going on for the production of biosurfactants from microbes. But still, many areas remain unexplored and need further investigation, such as:

AR prepared the draft of the manuscript under the supervision and guidance of AK. AK and JD revised and edited the manuscript. All authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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