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In the present work, we demonstrated the potential use of newly identified lipopeptides produced by B. mojavensis BI2 along with palm waste flour for the bioremediation of heavy metals contaminated water. The enhancement of radish seeds germination was used to evaluate the treatment efficiency. Firstly, better enhancement in the order of 3.8, 2.52, 1.5 and 5 were recorded respectively for 200 mg/L copper, lead, cobalt and mercury with respective lipopeptide quantities of the order of 200, 300, 200 and 400 mg/L. When studying the sequestration of increasing heavy metals concentration, BI2 lipopeptide was effective. Secondly, a mixed bioprocess was evaluated using palm waste flour as heavy metals sequester and BI2 lipopeptides as improver. Optimal biosorption of lead, copper, cobalt and mercury were obtained with 10 g/l waste, 1,000 mg/l metal and 200 mg/l BI2 lipopeptide for 1 hour. The addition of 200 mg/l BI2 lipopeptide improves the efficiency of the treatment significantly.

Glycolipids, consisting of a carbohydrate moiety linked to fatty acids, are microbial surface active compounds produced by various microorganisms. Glycolipids are characterized by highly structural diversity and have the ability to decrease the surface and interfacial tension at the surface and interface respectively. It presented initially a detailed classification of glycolipid including rhamnolipids, trehalolipids, mannosylerythritol-lipids, cellobiolipids; along with their producing strain. The review described the main functional properties of glycolipid including emulsification/de-emulsification capacity, foaming and moisturizing, viscosity reduction and hydrocarbon solubilizing and mobilizing capacities. Owing these properties, they can be applied in environmental fields as hydrocarbon emulsifiers, solubilizing and mobilizing agents, for their moisturizing capabilities and ability to reduce viscosity. The review will present a detailed classification of glycolipid biosurfactants, functional properties and the potential related applications in environment and bioremediation.

Detergent products are a formulated mixture of ingredients with a washing or cleaning power. The most active compounds involved in the cleaning process are the so-called surfactants; amphiphilic compounds with polar head and an-polar teal. They have the property to lower the surface tension (ST) of water, to adsorb to the interface and to reduce the interfacial tension (IFT) between two immiscible liquid. Then, they are very good at liberating dirt and to eliminate impurities. However, owing their chemical nature, they are characterized by their high toxicity and low biodegradability causing serious risks to natural ecosystems. Therefore, an urgent need was developed for the production of environment friendly detergent. Thus, developing eco-friendly, nonirritant, low-toxic, and high-efficient surface active ingredients for detergents is an ongoing challenge in the detergent field. To know, biosurfactants (BioS) or microbial surfactants are amphiphilic compounds having the ability to reduce the surface and interfacial tension. They are characterized by their higher biodegradability, low toxicity and eco-friendly. Thus, they can be the best substitutes of chemical surfactants in detergent formulation permitting the development of eco-friendly bio-based detergent formula. With this aim, we will discuss in the first part of the presented review detergent formula and surfactants as the base ingredients; their physic-chemical properties and higher toxicity. In the second part of the review paper, BioS as emerging ingredients for detergent formulation will be presented; their classification, physic-chemical and functional properties along with their potential application in detergent formulation.

The current work aims to optimize biological textile effluent treatment through the use of newly selected bacterial consortia composed of two strains: Citrobacter sedlakii RI11 and Aeromonas veronii GRI. We assessed the effect of SPB1 biosurfactant addition on color removal (CR). The process was optimized by a Box–Bhenken by examining the effect of pH, consortia density and biosurfactant value on treatment efficiency. Firstly, physicochemical analyses of the studied effluent revealed an alkaline pH along with a high content of suspended materials and large amounts of organic matter. Optimal CR and a chemical oxygen demand abatement of about 94 and 86% were obtained when treating the textile effluent at pH 5 with a total optical density of 0.4 and by incorporating 0.01% SPB1 biosurfactant. Additionally, an abolishment of phytotoxicity was registered after treatment optimization. The evaluations of the action mode of both selected bacteria during textile effluent treatment suggested the occurrence of biodegradation phenomena of dyes through enzymatic activities.

Lipopeptides biosurfactants (BioS) are natural surface-active compounds produced by a variety of microorganisms. They have great interest in environmental, biomedical and agro-industrial fields. However their large-scale application and production is limited by the cost of culture media and the low yield of production. Therefore, the improvement of the production yields and the development of efficient and cost-effective bioprocess became of a great interest. In this aim, we applied the response surface method to optimize an economic BioS production by a newly isolated strain Bacillus mojavensis BI2 on date Juice called “Luegmi” as unique carbon and nitrogen source. Using a Box-Bhenken design, we studied the effect of three independent variables on lipopeptide production; Leugmi concentration, Na2HPO4 and incubation time. The results of this study showed that Leugmi concentration at 25%, Na2HPO4 at 0.1% and incubation time of 24 h were optimal conditions for BioS production, with a maximum Surface Tension (ST) decreasing capacity of 55% corresponding to 27 mN/m and an Oil Dispersing Activity (ODA) of 30 cm2 corresponding to a diameter of 6 cm. Preliminary characterization of the BioS produced on Luegmi by UV-Spectra and Thin Layer Chromatography showed its lipopeptide nature. Physic-chemical characterization of the produced lipopeptide on Leugmi showed its great surface activities and stabilities at different pH, temperature and salts concentration. The results of this study suggested that Leugmi, an agricultural byproducts can be used as a low-cost substrate to enhance the yield of lipopeptide BioS with great surface activities for potential environmental application.

Aiming the production of lipopeptides biosurfactants (BioS), we isolated a new strain identified as Bacillus subtilis ZNI5 from a hydrocarbon contaminated soil. Lipopeptides purification by anionic exchange chromatography and identification by Reverse Phase High Performance Liquid Chromatography–Mass Spectrometry (RP-HPLC–MS) permitted the selection of different homologues divided into four families. The first family corresponds to Surfactin isoforms with molecular weights of 1007, 1021 and 1035 Da; the second family correspond to Iturin isoforms with molecular weights of 1028, 1042 and 1056 Da; the third family correspond to a single isoform called Licheniformin with molecular weight of 1410 and the fourth family correspond to newly identified isoforms named Inesfactin with molecular weights of 973 and 987 Da. Regarding the functional properties of the ZNI5 BioS, it was characterized as a powerful surface-active agent that decreases the Surface Tension of water from 72 mN/m to about 32 mN/m with a CMC value of 350 mg/L more efficient than chemical surfactants (Triton X100; CTAB and SDS). Moreover, it has the capacity to disperse oil to about 80 mm at a concentration of 800 mg/L showing close efficiencies to the listed chemical surfactants. In addition, the physic–chemical characterization of the surface activities of ZNI5 BioS showed great thermal, pH and salts activity and stability enabling its use in the bioremediation fields and for diverse industrial applications.

Biosurfactants are surface-active biomolecules that are produced by a variety of microorganisms. They have gained biotechnologist interest for high diversity and their efficient action in comparison to synthetic emulsifiers. So, we discussed a wide array of screening method based on direct and indirect surface and interfacial tension measurements. Also, this review describes biosurfactant physicochemical properties and natural role in the environment. Also, it presents their tolerance to extreme conditions of temperature, pH and ionic strength, low toxicity and biodegradability. Functional properties like emulsification, foaming, solubilizing and membrane permeabilizing activities were also discussed along with their related application.

The present study summarizes the valorization of date flour by the production of lipopeptide biosurfactant (BioS) by Bacillus subtilis ZNI5 (MW091416). A Taguchi design permitted the formulation of a medium composed only of 6% date flour and 0.5% yeast extract within 2 days of incubation at 150 rpm with a maximal surface tension (ST) reduction of about 27.8 mN/m. The characterization of the lipopeptide shows a CMC value of about 400 mg/L with a minimal ST of 30 mN/m and an ability to disperse oil to about 80 mm at 800 mg/L. Having reduced phytotoxicity, the ZNI5 BioS and ZNI5 strain were assayed for Copper and Cobalt chelation and biosorption. The improvement of the germination index of radish seeds irrigated by the treated contaminated water showed the great potential application of ZNI5 lipopeptide in the bioremediation of heavy metals.

Bioremediation, involving the use of microorganisms to detoxify or remove pollutants, is the most interesting strategy for hydrocarbon remediation. In this aim, four hydrocarbon-degrading bacteria were isolated from oil-contaminated soil in Tunisia. They were identified by the 16S rDNA sequence analysis, as Lysinibacillus bronitolerans RI18 (KF964487), Bacillus thuringiensis RI16 (KM111604), Bacillus weihenstephanensis RI12 (KM094930), and Acinetobacter radioresistens RI7 (KJ829530). Moreover, a lipopeptide biosurfactant produced by Bacillus subtilis SPB1, confirmed to increase diesel solubility, was tested to increase diesel biodegradation along with co-inoculation with two biosurfactant-producing strains. Culture studies revealed the enhancement of diesel biodegradation by the selected consortium with the addition of SPB1 lipopeptide and in the cases of co-inoculation by biosurfactant-producing strain. In fact, an improvement of about 38.42 and 49.65 % of diesel degradation was registered in the presence of 0.1 % lipopeptide biosurfactant and when culturing B. subtilis SPB1 strain with the isolated consortium, respectively. Furthermore, the best improvement, evaluated to about 55.4 %, was recorded when using the consortium cultured with B. subtilis SPB1 and A. radioresistens RI7 strains. Gas chromatography analyses were correlated with the gravimetric evaluation of the residual hydrocarbons. Results suggested the potential applicability of the selected consortium along with the ex situ- and in situ-added biosurfactant for the effective bioremediation of diesel-contaminated water and soil.

High molecular weight bioemulsifiers are amphipathic polysaccharides, proteins, lipopolysaccharides, lipoproteins, or complex mixtures of these biopolymers, produced by a wide variety of microorganisms. They are characterized by highly structural diversity and have the ability to decrease the surface and interfacial tension at the surface and interface respectively and/or emulsify hydrophobic compounds. Emulsan, fatty acids, phospholipids, neutral lipids, exopolysaccharides, vesicles and fimbriae are among the most popular high molecular weight bioemulsifiers. They have great physic-chemical properties like tolerance to extreme conditions of pH, temperature and salinity, low toxicity and biodegradability. Owing their emulsion forming and breaking capacities, solubilization, mobilization and dispersion activities and their viscosity reduction activity; they possess great environmental application as enhancer of hydrocarbon biodegradation and for microbial enhanced oil recovery. Besides, they are applied in biomedical fields for their antimicrobial and anti-adhesive activities and involvement in immune responses.