Biosurfactant production: emerging trends and promising strategies

Remediation of oil-polluted soil using anionic and non-ionic composite biosurfactants

Petroleum hydrocarbons as pervasive pollutants pose a significant threat to soil ecology and human health. Surfactant washing as an established technique can effectively remediate soils contaminated by hydrocarbons. Biosurfactants, which combine the properties of surfactants and environmental compatibility, have attracted increasing interest. However, due to the high production cost of biosurfactants, their practical application is restricted. This study addressed these limitations by selecting two biosurfactants, β-cyclodextrin (C1) and sodium carboxymethyl cellulose (C2), and developed a promising cleaning agent formula through compounding and the addition of suitable additives. When the volume ratio of C1 to C2 was 8:2 and an 8 g/L mixture of sodium humate and sodium carbonate electrolyte was added, the surfactant system's surface tension reached a minimum, yielding optimal oil removal. The formation and synergistic behaviour of mixed micelles of surfactants were explained using ideal solution theory and the Rubingh model. By optimising the oil washing process parameters - normal temperature of 25 °C, pH 11, washing time of 2 h, solid-liquid ratio of 1:5, and oscillation frequency of 200 r/min - the oil removal rate achieved 76%. This cleaning agent, characterised by low production cost, straightforward application, environmental compatibility, and rapid, significant cleaning effect, shows potential for field-scale purification of petroleum-contaminated soil.

Biosurfactant complexed with arginine has antibiofilm activity against methicillin-resistant Staphylococcus aureus

Aim: The present study investigated the antimicrobial effectiveness of a rhamnolipid complexed with arginine (RLMIX_Arg) against planktonic cells and biofilms of methicillin-resistant Staphylococcus aureus (MRSA). Methodology: Susceptibility testing was performed using the Clinical & Laboratory Standards Institute protocol: M07-A10, checkerboard test, biofilm in plates and catheters and flow cytometry were used. Result: RLMIX_Arg has bactericidal and synergistic activity with oxacillin. RLMIX_Arg inhibits the formation of MRSA biofilms on plates at sub-inhibitory concentrations and has antibiofilm action against MRSA in peripheral venous catheters. Catheters impregnated with RLMIX_Arg reduce the formation of MRSA biofilms. Conclusion: RLMIX_Arg exhibits potential for application in preventing infections related to methicillin-resistant S. aureus biofilms.

Valorization of waste engine oil to mono- and di-rhamnolipid in a sustainable approach to circular bioeconomy

This study aims to valorize waste engine oil (WEO) for synthesizing economically viable biosurfactants (rhamnolipids) to strengthen the circular bioeconomy concept. It specifically focuses on investigating the influence of key bioprocess parameters, viz. agitation and aeration rates, on enhancing rhamnolipid yield in a fed-batch fermentation mode. The methodology involves conducting experiments in a stirred tank bioreactor (3 L) using Pseudomonas aeruginosa gi |KP 163922| as the test organism. Central composite design and response surface methodology (CCD-RSM) are employed to design the experiments and analyze the effects of agitation and aeration rates on various parameters, including dry cell biomass (DCBM), surface tension, tensoactivity, and rhamnolipid yield. It is also essential to determine the mechanistic pathway of biosurfactant production followed by the strain using complex hydrophobic substrates such as WEO. The study reveals that optimal agitation and aeration rates of 200 rpm and 1 Lpm result in the highest biosurfactant yield of 29.76 g/L with minimal surface tension (28 mN/m). Biosurfactant characterization using FTIR, 1H NMR, and UPLC-MS/MS confirm the presence of dominant molecular ion peaks m/z 543.9 and 675.1. This suggests that the biosurfactant is a mixture of mono- and di-rhamnolipids (RhaC10C10, RhaRhaC10C12:1, RhaRhaC12:1C10). The findings present a sustainable approach for biosurfactant production in a fed-batch bioreactor. This research opens the possibility of exploring the use of pilot or large-scale bioreactors for biosurfactant production in future investigations.

Latest Trends in Lipase-Catalyzed Synthesis of Ester Carbohydrate Surfactants: From Key Parameters to Opportunities and Future Development

Carbohydrate-based surfactants are amphiphilic compounds containing hydrophilic moieties linked to hydrophobic aglycones. More specifically, carbohydrate esters are biosourced and biocompatible surfactants derived from inexpensive renewable raw materials (sugars and fatty acids). Their unique properties allow them to be used in various areas, such as the cosmetic, food, and medicine industries. These multi-applications have created a worldwide market for biobased surfactants and consequently expectations for their production. Biobased surfactants can be obtained from various processes, such as chemical synthesis or microorganism culture and surfactant purification. In accordance with the need for more sustainable and greener processes, the synthesis of these molecules by enzymatic pathways is an opportunity. This work presents a state-of-the-art lipase action mode, with a focus on the active sites of these proteins, and then on four essential parameters for optimizing the reaction: type of lipase, reaction medium, temperature, and ratio of substrates. Finally, this review discusses the latest trends and recent developments, showing the unlimited potential for optimization of such enzymatic syntheses.

Advances in the co-production of biosurfactant and other biomolecules: statistical approaches for process optimization

An efficient microbial conversion for simultaneous synthesis of multiple high-value compounds, such as biosurfactants and enzymes, is one of the most promising aspects for an economical bioprocess leading to a marked reduction in production cost. Although biosurfactant and enzyme production separately have been much explored, there are limited reports on the predictions and optimization studies on simultaneous production of biosurfactants and other industrially important enzymes, including lipase, protease, and amylase. Enzymes are suited for an integrated production process with biosurfactants as multiple common industrial processes and applications are catalysed by these molecules. However, the complexity in microbial metabolism complicates the production process. This study details the work done on biosurfactant and enzyme co-production and explores the application and scope of various statistical tools and methodologies in this area of research. The use of advanced computational tools is yet to be explored for the optimization of downstream strategies in the co-production process. Given the complexity of the co-production process and with various new methodologies based on artificial intelligence (AI) being invented, the scope of AI in shaping the biosurfactant-enzyme co-production process is immense and would lead to not only efficient and rapid optimization, but economical extraction of multiple biomolecules as well.

Carbon and nitrogen optimization in solid-state fermentation for sustainable sophorolipid production using industrial waste

The use of alternative feedstocks such as industrial or food waste is being explored for the sustainable production of sophorolipids (SLs). Microbial biosurfactants are mainly produced via submerged fermentation (SmF); however, solid-state fermentation (SSF) seems to be a promising alternative for using solid waste or byproducts that could not be exploited by SmF. Applying the advantages that SSF offers and with the aim of revalorizing industrial organic waste, the impact of carbon and nitrogen sources on the relationship between yeast growth and SL production was analyzed. The laboratory-scale system used winterization oil cake as the solid waste for a hydrophobic carbon source. Pure hydrophilic carbon (glucose) and nitrogen (urea) sources were used in a Box-Behnken statistical design of experiments at different ratios by applying the response surface methodology. Optimal conditions to maximize the production and productivity of diacetylated lactonic C18:1 were a glucose:nitrogen ratio of 181.7:1.43 (w w-1 based on the initial dry matter) at a fermentation time of 100 h, reaching 0.54 total gram of diacetylated lactonic C18:1 with a yield of 0.047 g per gram of initial dry mass. Moreover, time course fermentation under optimized conditions increased the SL crude extract and diacetylated lactonic C8:1 production by 22% and 30%, respectively, when compared to reference conditions. After optimization, industrial wastes were used to substitute pure substrates. Different industrial sludges, OFMSW hydrolysate, and sweet candy industry wastewater provided nitrogen, hydrophilic carbon, and micronutrients, respectively, allowing their use as alternative feedstocks. Sweet candy industry wastewater and cosmetic sludge are potential hydrophilic carbon and nitrogen sources, respectively, for sophorolipid production, achieving yields of approximately 70% when compared to the control group.

An insight into the utilization of microbial biosurfactants pertaining to their industrial applications in the food sector

Microbial biosurfactants surpass synthetic alternatives due to their biodegradability, minimal toxicity, selective properties, and efficacy across a wide range of environmental conditions. Owing to their remarkable advantages, biosurfactants employability as effective emulsifiers and stabilizers, antimicrobial and antioxidant attributes, rendering them for integration into food preservation, processing, formulations, and packaging. The biosurfactants can also be derived from various types of food wastes. Biosurfactants are harnessed across multiple sectors within the food industry, ranging from condiments (mayonnaise) to baked goods (bread, muffins, loaves, cookies, and dough), and extending into the dairy industry (cheese, yogurt, and fermented milk). Additionally, their impact reaches the beverage industry, poultry feed, seafood products like tuna, as well as meat processing and instant foods, collectively redefining each sector's landscape. This review thoroughly explores the multifaceted utilization of biosurfactants within the food industry as emulsifiers, antimicrobial, antiadhesive, antibiofilm agents, shelf-life enhancers, texture modifiers, and foaming agents.

Importance of microbial amphiphiles: interaction potential of biosurfactants, amyloids, and other exo-polymeric-substances

Microorganisms produce a diverse group of biomolecules having amphipathic nature (amphiphiles). Microbial amphiphiles, including amyloids, bio-surfactants, and other exo-polymeric substances, play a crucial role in various biological processes and have gained significant attention recently. Although diverse in biochemical composition, these amphiphiles have been reported for common microbial traits like biofilm formation and pathogenicity due to their ability to act as surface active agents with active interfacial properties essential for microbes to grow in various niches. This enables microbes to reduce surface tension, emulsification, dispersion, and attachment at the interface. In this report, the ecological importance and biotechnological usage of important amphiphiles have been discussed. The low molecular weight amphiphiles like biosurfactants, siderophores, and peptides showing helical and antimicrobial activities have been extensively reported for their ability to work as quorum-sensing mediators. While high molecular weight amphiphiles make up amyloid fibers, exopolysaccharides, liposomes, or magnetosomes have been shown to have a significant influence in deciding microbial physiology and survival. In this report, we have discussed the functional similarities and biochemical variations of several amphipathic biomolecules produced by microbes, and the present report shows these amphiphiles showing polyphyletic and ecophysiological groups of microorganisms and hence can `be replaced in biotechnological applications depending on the compatibility of the processes.

Rhamnolipid production by Pseudomonas aeruginosa (SSL-4) on waste engine oil (WEO): Taguchi optimization, soil remediation, and phytotoxicity investigation

ABSTRACTEnvironmental concerns and rising biosurfactant demand emphasize the need for this study. The objective is to maximize rhamnolipid-biosurfactant production by Pseudomonas aeruginosa (SSL-4) utilizing waste engine oil (WEO) as the sole substrate for use in soil bioremediation and commercial production. Using an L16 Taguchi orthogonal array, a signal-to-noise ratio, and an analysis of variance (ANOVA), the effects of environmental (pH, incubation temperature) and dietary parameters (carbon source concentration, carbon/nitrogen (C/N) and carbon/phosphorus (C/P) ratio) are examined. Variations of the following parameters were made within a carefully selected range: incubation temperature of 25-40℃, pH range of 5-11, WEO concentration of 1-7% (v/v), and C/N and C/P ratios of 10-40. Response variables in this batch study include surface tension reduction (mN/m), dry cell biomass (DCBM) (g/L), and rhamnolipids yield based on substrate consumption, YP/S (g/g). Rhamnolipid was synthesized under optimal conditions, providing a yield of 21.42 g/g. The oil recovery of 74.05 ± 1.481% was achieved from oil-contaminated soil at a CMC of ∼70 mg/L. FTIR, 1H NMR, and UPLC-MS techniques were utilized for the characterization of rhamnolipids, and AAS for determining heavy metals concentration in WEO and residual waste engine oil (RWEO). The Germination Index (GI) of ∼82.55% indicated no phytotoxicity associated with synthesized rhamnolipid.

A new biosurfactant-producing strain, Fictibacillus nanhaiensis ME46, isolated from an oil field in China

The genus Fictibacillus contains twelve species significant in the synthesis of cellulose-degrading enzymes and phenylalanine dehydrogenase, isolated mainly from marine sedimentary environments. Here, we report a new biosurfactant-producing strain, Fictibacillus nanhaiensis ME46, isolated from Daqing oil field in China. The biosurfactant extracted from Strain ME46 was determined as surfactin, one of the representative families of lipopeptide biosurfactants. The yield of the surfactin produced by strain ME46 was 0.62 g·L-1 as determined by high-performance liquid chromatography, and the critical micelle concentration (CMC) of the surfactin was estimated to be about 68 mg·L-1 and the surface tension at CMC was 35.1 mN·m-1. This study extended our knowledge about the role of the species Fictibacillus nanhaiensis in the ecosystem of natural environments such as the oil field.

A comprehensive review on production of bio-surfactants by bio-degradation of waste carbohydrate feedstocks: an approach towards sustainable development

The advancement of science and technology demands chemistry which is safer, smarter and green by nature. The sustainability of science thus requires well-behaved alternates that best suit the demand. Bio-surfactants are surface active compounds, established to affect surface chemistry. In general, microbial bio-surfactants are a group of structurally diverse molecules produced by different microbes. A large number of bio-surfactants are produced during hydrocarbon degradation by hydrocarbonoclistic microorganisms during their own growth on carbohydrates and the production rate is influenced by the rate of degradation of carbohydrates. The production of such biological surfactants is thus of greater importance. This write up is a dedicated review to update the existing knowledge of inexpensive carbohydrate sources as substrates, microorganisms and technologies of biosurfactant production. This is an economy friendly as well as sustainable approach which will facilitate achieving some sustainable development goals. The production is dependent on the fermentation strategies, different factors of the microbial culture broth and downstream processing; these all have been elaborately presented in this article.

Biotechnological potential of microbial bio-surfactants, their significance, and diverse applications

Globally, there is a huge demand for chemically available surfactants in many industries, irrespective of their detrimental impact on the environment. Naturally occurring green sustainable substances have been proven to be the best alternative for reducing reliance on chemical surfactants and promoting long-lasting sustainable development. The most frequently utilized green active biosurfactants, which are made by bacteria, yeast, and fungi, are discussed in this review. These biosurfactants are commonly originated from contaminated sites, the marine ecosystem, and the natural environment, and it holds great potential for environmental sustainability. In this review, we described the importance of biosurfactants for the environment, including their biodegradability, low toxicity, environmental compatibility, and stability at a wide pH range. In this review, we have also described the various techniques that have been utilized to characterize and screen the generation of microbial biosurfactants. Also, we reviewed the potential of biosurfactants and its emerging applications in the foods, cosmetics, pharmaceuticals, and agricultural industries. In addition, we also discussed the ways to overcome problems with expensive costs such as low-cost substrate media formulation, gravitational techniques, and solvent-free foam fractionation for extraction that could be employed during biosurfactant production on a larger scale.

Spent coffee grounds as feedstock for the production of biosurfactants and the improved recovery of melanoidins

Spent coffee grounds (SCG) are wastes generated in high amounts worldwide. Their composition makes them a promising feedstock for biotechnological processes. Here we show that the production of the biosurfactant surfactin by submerged culture of a Bacillus subtilis strain growing on SCG is possible, reaching concentrations up to 8.8 mg/L when using SCG at 8.3 g/L in the medium. In addition, we report a synergy between the production of surfactin and the recovery of melanoidins, an added-value compound already present in SCG. More specifically, the concentration of melanoidins in the culture medium increased between 2.1 and 2.5 times thanks to the presence of the B. subtilis in the culture. Furthermore, we have observed a strong interaction between surfactin and melanoidin aggregates through dynamic light scattering measurements, and that both of them can be co-purified with an acid precipitation. We have also characterized the interfacial and antioxidant properties of the cell-free supernatant and surfactin extract, as well as the distribution of the congeners of the biosurfactant. Altogether, this work describes a promising approach to obtain biosurfactants and antioxidant molecules in a single operation, which can be used to design several new formulations of interest for bioremediation, amendment of soils, food and cosmetics.

Sophorolipid-based microemulsion delivery system: Multifaceted enhancement of physicochemical properties of xanthohumol

Xanthohumol (XN) has numerous compelling physiological activities, but the poor solubility and stability severely limit its utilization. Therefore, a microemulsion (ME) delivery system based on biosurfactant sophorolipids (SLs) was established and its improvement on physicochemical properties of XN was investigated. The results showed that the systems increased the solubility of XN by about 4000 times, and its half-life during storage was extended to over 150 days. Partial replacement of Tween 80 with SL did not greatly affect their ability to form O/W subregions (in the high aqueous phase), but further improved the solubilization efficiency, storage stability, and antioxidant properties of XN. In vitro models revealed the release profile of XN from the systems followed non-Fickian diffusion, and the ME structure markedly strengthened its digestive stability and bioaccessibility. These results indicated that SL-based ME systems had great potential as a green solubilization and delivery method for XN and other hydrophobic drugs.

Structural Diversity of the Lipopeptide Biosurfactant Produced by a Newly Isolated Strain, Geobacillus thermodenitrifcans ME63

The genus Geobacillus is active in degradation of hydrocarbons in thermophilic and facultative environments since it was first reported in 1920. Here, we report a new strain, Geobacillus thermodenitrificans ME63, isolated from an oilfield with the ability of producing the biosurfactant. The composition, chemical structure, and surface activity of the biosurfactant produced by G. thermodenitrificans ME63 were investigated by using a combination of the high-performance liquid chromatography, time-of-flight ion mass spectrometry, and surface tensiometer. The biosurfactant produced by strain ME63 was identified as surfactin with six variants, which is one of the representative family of lipopeptide biosurfactants. The amino acid residue sequence in the peptide of this surfactin is N-Glu → Leu → Leu → Val → Leu → Asp → Leu-C. The critical micelle concentration (CMC) of the surfactin is 55 mg L^-1, and the surface tension at CMC is 35.9 mN m^-1, which is promising in bioremediation and oil recovery industries. The surface activity and emulsification properties of biosurfactants produced by G. thermodenitrificans ME63 showed excellent resistance to temperature changes, salinity changes, and pH changes.

Green dispersants for oil spill response: A comprehensive review of recent advances

Green dispersants are so-called "green" because they are renewable (from bio-based sources), non-volatile (from ionic liquids), or are from naturally available solvents (vegetable oils). In this review, the effectiveness of different types of green dispersants, namely, protein isolates and hydrolysates from fish and marine wastes, biosurfactants from bacterial and fungal strains, vegetable-based oils such as soybean lecithin and castor oils, as well as green solvents like ionic liquids are reviewed. The challenges and opportunities offered by these green dispersants are also elucidated. The effectiveness of these dispersants varies widely and depends on oil type, dispersant hydrophilicity/hydrophobicity, and seawater conditions. However, their advantages lie in their relatively low toxicity and desirable physico-chemical properties, which make them potentially ecofriendly and effective dispersants for future oil spill response.

Evaluation of the potential herb-drug interaction between Bojungikki-tang and PD-L1 immunotherapy in a syngeneic mouse model

Atezolizumab (a PD-L1 inhibitor) has shown remarkable efficacy and tolerability in various cancer types. Despite its efficacy and safety, atezolizumab monotherapy has limitations, such as acquired resistance and adverse events. Bojungikki-tang (BJIKT) is an herbal decoction widely prescribed in Asian countries and used to treat cancer-related symptoms including fatigue, appetite loss, gastrointestinal disorders, and other side effects from cancer therapy. Due to its immunomodulatory effects, Bojungikki-tang has been investigated as a combined treatment with anticancer agents. We evaluated the potential drug-drug interaction (DDI) between Bojungikki-tang and the anti-PD-L1 antibody based on the Food and Drug Administration (FDA) guidelines. In the study, we conducted an in vivo drug-drug interaction study using a syngeneic mouse model of CMT-167 in C57BL/6. We then determined the antibody concentrations to evaluate the pharmacokinetic (PK) drug-drug interaction and measured variable biomarkers related to therapeutic efficacy and immune response. The pharmacodynamic (PD) drug-drug interaction study investigated changes in response between anti-PD-L1 antibody monotherapy and combination therapy. Using the pharmacokinetic and pharmacodynamic data, we conducted a statistical analysis to assess drug-drug interaction potential. In the presence of Bojungikki-tang, the pharmacokinetic characteristics of the anti-PD-L1 antibody were not changed. This study suggested that combination treatment with Bojungikki-tang and atezolizumab is a safe treatment option for non-small cell lung cancer. Clinical studies are warranted to confirm this finding.

Optimization of the Operational Conditions to Produce Extracellular and Cell-Bound Biosurfactants by Aneurinibacillus aneurinilyticus Using Corn Steep Liquor as a Unique Source of Nutrients

The relevance of this work lies in the fact that it is the first time that corn steep liquor (CSL) has been proposed as a unique source of nutrients for producing biosurfactants in a controlled fermentation and Aneurinibacillus aneurinilyticus, isolated from CSL, has been evaluated for producing extracellular and cell-bound biosurfactants in a controlled fermentation, using secondary raw materials as a source of nutrients. In the present study, A. aneurinilyticus was inoculated into the culture medium containing sterilized CSL solutions (100–400 g L−1) and incubated using different temperatures (20–60 °C) and fermentation times (8–30 days). The dependent variables under study were the concentration of extracellular biosurfactants and cell-bound biosurfactant production in terms of critical micellar concentration (CMC), as well as the C/N ratio for cell-bound biosurfactant extracts. It was observed that CSL could increase the concentration of extracellular biosurfactants produced by A. aneurinilyticus if these were fermented during 19 days at 40 °C, using 250 g L−1 of CSL; a mean value of 6 g L−1 for extracellular biosurfactants and favorable CMC concentrations enabled the detection of cell-bound biosurfactant extracts under these conditions. Hence, these conditions could be considered optimal for producing both extracellular and cell-bound biosurfactants from CSL.

Enhanced biosurfactant production by Bacillus subtilis SPB1 using developed fed-batch fermentation: effects of glucose levels and feeding systems

Biosurfactants stand for highly useful and promising compounds. They basically serve for a variety of applications in multiple industries and aspects of human life. Therefore, it is highly required to improve their production yield especially through the development of new and more efficient fermentation processes. In this aim, batch and fed-batch were studied and compared in terms of their effective biosurfactant production by Bacillus subtilis SPB1. Experiments of fed-batch fermentations were carried out through three different glucose feeding strategies, namely the pulsed, the constant Donespeed and the exponential feeding. The comparison between different fermentation processes revealed that fed-batch process proved to be a more efficient cultivation strategy than the batch process in terms of cell biomass, biosurfactant production and productivity. Among the three different feeding strategies, the exponential feeding process achieved the highest fermentation results of final biosurfactant concentration. The latter increased more than twofolds compared to batch fermentation.

Functional genomic analysis of an efficient indole degrading bacteria strain Alcaligenes faecalis IITR89 and its biodegradation characteristics

Indole is a nitrogenous heterocyclic aromatic pollutant often detected in various environments. An efficient indole degrading bacterium strain IITR89 was isolated from River Cauvery, India, and identified as Alcaligenes faecalis subsp. phenolicus. The bacterium was found to degrade ~ 95% of 2.5 mM (293.75 mg/L) of indole within 18 h utilizing it as a sole carbon and energy source. Based on metabolite identification, the metabolic route of indole degradation is indole → (indoxyl) → isatin → (anthranilate) → salicylic acid → (catechol) → (Acetyl-CoA) → and further entering into TCA cycle. Genome sequencing of IITR89 revealed the presence of gene cluster dmpKLMNOP, encoding multicomponent phenol hydroxylase; andAbcd gene cluster, encoding anthranilate 1,2-dioxygenase ferredoxin subunit (andAb), anthranilate 1,2-dioxygenase large subunit (andAc), and anthranilate 1,2-dioxygenase small subunit (andAd); nahG, salicylate hydroxylase; catA, catechol 1,2-dioxygenase; catB, cis, cis-muconate cycloisomerase; and catC, muconolactone D-isomerase which play an active role in indole degradation. The findings strongly support the degradation potential of strain IITR89 and its possible application for indole biodegradation.

The paradigm of prophylactic viral outbreaks measures by microbial biosurfactants

The recent emergence and outbreak of the COVID-19 pandemic confirmed the incompetence of countries across the world to deal with a global public health emergency. Although the recent advent of vaccines is an important prophylactic measure, effective clinical therapy for SARS-Cov-2 is yet to be discovered. With the increasing mortality rate, research has been focused on understanding the pathogenic mechanism and clinical parameters to comprehend COVID-19 infection and propose new avenues for naturally occurring molecules with novel therapeutic properties to alleviate the current situation. In accordance with recent clinical studies and SARS-CoV-2 infection markers, cytokine storm and oxidative stress are entwined pathogenic processes in COVID-19 progression. Lately, Biosurfactants (BSs) have been studied as one of the most advanced biomolecules of microbial origin with anti-inflammatory, antioxidant, antiviral properties, antiadhesive, and antimicrobial properties. Therefore, this review inspects available literature and proposes biosurfactants with these properties to be encouraged for their extensive study in dealing with the current pandemic as new pharmaceutics in the prevention and control of viral spread, treating the symptoms developed after the incubation period through different therapeutic approaches and playing a potential drug delivery model.

Biosurfactant from Candida: sources, classification, and emerging applications

Biosurfactants are surface-active molecules that are synthesized by many microorganisms like fungi, bacteria, and yeast. These molecules are amphiphilic in nature, possessing emulsifying ability, detergency, foaming, and surface-activity like characteristics. Yeast species belongs to the genus Candida has gained globally enormous interest because of the diverse properties of biosurfactants produced by theme. In contrast to synthetic surfactants, biosurfactants are claimed to be biodegradable and non-toxic which labels them as a potent industrial compound. Biosurfactants produced by this genus are reported to possess certain biological activities, such as anticancer and antiviral activities. They also have potential industrial applications in bioremediation, oil recovery, agricultural, pharmaceutical, biomedical, food, and cosmetic industries. Various species of Candida have been recognized as biosurfactant producers, including Candida petrophilum, Candida bogoriensis, Candida antarctica, Candida lipolytica, Candida albicans, Candida batistae, Candida albicans, Candida sphaerica, etc. These species produce various forms of biosurfactants, such as glycolipids, lipopeptides, fatty acids, and polymeric biosurfactants, which are distinct according to their molecular weights. Herein, we provide a detailed overview of various types of biosurfactants produced by Candida sp., process optimization for better production, and the latest updates on the applications of these biosurfactants.

Valorization of Food Waste to Produce Value-Added Products Based on Its Bioactive Compounds

The rapid growth of the global population and changes in lifestyle have led to a significant increase in food waste from various industrial, agricultural, and household sources. Nearly one-third of the food produced annually is wasted, resulting in severe resource depletion. Food waste contains rich organic matter, which, if not managed properly, can pose a serious threat to the environment and human health, making the proper disposal of food waste an urgent global issue. However, various types of food waste, such as waste from fruit, vegetables, grains, and other food production and processing, contain important bioactive compounds, such as polyphenols, dietary fiber, proteins, lipids, vitamins, organic acids, and minerals, some of which are found in greater quantities in the discarded parts than in the parts accepted by the market. These bioactive compounds offer the potential to convert food waste into value-added products, and fields including nutritional foods, bioplastics, bioenergy, biosurfactants, biofertilizers, and single cell proteins have welcomed food waste as a novel source. This review reveals the latest insights into the various sources of food waste and the potential of utilizing bioactive compounds to convert it into value-added products, thus enhancing people’s confidence in better utilizing and managing food waste.

Comparative life cycle assessment for the manufacture of bio-detergents

The increasing consumption of cleaning products deteriorates water resources due to harmful components such as phosphorus (P) and nitrogen (N) compounds, oils, bleach, and acids, typical compounds in traditional detergents. The use of biodegradable detergents as an environmentally friendly alternative has been proposed in different regions. In Colombia, resolution 1770/2018 sets a minimum biodegradability rate of 60% for the surfactants present in liquid detergents, which would reduce to a similar extent the impacts on water after their use. However, the environmental impacts of the supply chain of these detergents and their raw materials have not been evaluated so far. This study presents an environmental life cycle assessment of petroleum-based liquid detergents and a comparison to traditional solid detergents, based on the ISO 14040 standard and the ReCiPe-2016 impacts assessment method. A novel bio-detergent containing anionic plant-based surfactants was proposed in this analysis. The impacts of packaging and the distribution of the product to consumers were also considered. Raw materials contributed to 91% of the total of 314 g of CO₂ eq generated per liter of liquid detergent, where the production of fatty alcohol sulfate and PET packaging shared 78.8% and 12.2% of the total impact, respectively. It was also determined that 5.4 L of water are consumed and 0.09 g of P eq and 0.1 g of N eq are emitted per liter of detergent. This liquid detergent presented better environmental performance than traditional detergents in all the impact categories, except for the fossil resource scarcity category. The evaluated detergent would significantly mitigate the generation of negative effects on ecosystems. Moreover, the substitution of PET for HDPE packaging could reduce the impacts on freshwater eutrophication by 10%, although the carbon footprint can slightly increase, which could be compensated due to its higher recyclability rate. In contrast, the proposed bio-detergent would not have significant benefits and would negatively affect water consumption and land use in its supply chain.

Sophorolipids: A comprehensive review on properties and applications

Sophorolipids are surface-active glycolipids produced by several non-pathogenic yeast species and are widely used as biosurfactants in several industrial applications. Sophorolipids provide a plethora of benefits over chemically synthesized surfactants for certain applications like bioremediation, oil recovery, and pharmaceuticals. They are, for instance less toxic, more benign and environment friendly in nature, biodegradable, freely adsorb to different surfaces, self-assembly in hydrated solutions, robustness for industrial applications etc. These miraculous properties result in valuable physicochemical attributes such as low critical micelle concentrations (CMCs), reduced interfacial surface tension, and capacity to dissolve non-polar components. Moreover, they exhibit a diverse range of physicochemical, functional, and biological attributes due to their unique molecular composition and structure. In this article, we highlight the physico-chemical properties of sophorolipids, how these properties are exploited by the human community for extensive benefits and the conditions which lead to their unique tailor-made structures and how they entail their interfacial behavior. Besides, we discuss the advantages and disadvantages associated with the use of these sophorolipids. We also review their physiological and functional attributes, along with their potential commercial applications, in real-world scenario. Biosurfactants are compared to their man-made equivalents to show the variations in structure-property correlations and possible benefits. Those attempting to manufacture purported natural or green surfactant with innovative and valuable qualities can benefit from an understanding of biosurfactant features structured along the same principles. The uniqueness of this review article is the detailed physico-chemical study of the sophorolipid biosurfactant and how these properties helps in their usage and detailed explicit study of their applications in the current scenario and also covering their pros and cons.

Production and characterization of bioemulsifier by Parapedobacter indicus

The current study evaluated Parapedobacter indicus MCC 2546 for its potential to produce a bioemulsifier (BE). Screening methods performed for BE production by P. indicus MCC 2546 showed good lipase activity, positive drop collapse test, and oil-spreading activity. Furthermore, it showed maximum emulsification activity (225 EU/ml) and emulsification index (E24 50%) at 37°C in Luria Bertani broth at 72 h with olive oil as a substrate. The optimal pH and NaCl concentration for maximum emulsification activity were 7 and 1%, respectively. P. indicus MCC 2546 lowered the surface tension of the culture medium from 59.65 to 50.42 ± 0.78 mN/m. BE produced was composed of 70% protein and 30% carbohydrate, which showed the protein-polysaccharide nature of the BE. Furthermore, Fourier transform infrared spectroscopy analysis confirmed the same. P. indicus MCC 2546 showed a catecholate type of siderophore production. This is the first report on BE and siderophore production by the genus Parapedobacter.

Experimental investigation for treating ibuprofen and triclosan by biosurfactant from domestic wastewater

The presence of emerging pollutants of pharmaceutical products and personal care products (PPCPs) in the aquatic environment overspreads the threat on living beings. Bioremediation is a promising option for treating wastewater. In the present study, an experimental investigation was carried out to produce a biosurfactant by Pseudomonas aeruginosa (MTCC 1688) for the removal of Ibuprofen (IBU) and Triclosan (TCS) from domestic wastewater. It was performed in three stages. Firstly, the production and optimization of biosurfactant was carried out to arrive at the best combination of crude sunflower oil, sucrose and ammonium bicarbonate (10%: 5.5 g/L: 1 g/L) to yield effective biosurfactant production (crude biosurfactant) and further extended to achieve critical micelle concentration (CMC) formation by dilution (biosurfactant at 10.5%). The stability of the biosurfactant was also confirmed. Biosurfactant showed a reduction in the surface tension to 41 mN/m with a yield concentration of 11.2 g/L. Secondly, its effectiveness was evaluated for the removal of IBU and TCS from the domestic wastewater collected during the dry and rainy seasons. Complete removal of IBU was achieved at 36 h & 6 h and TCS at 6 h & 1 h by crude biosurfactant and biosurfactant at CMC formation for the dry season sample. IBU removal was achieved in 2 h by both crude and biosurfactant at CMC and no TCS was detected in the rainy season sample. Thirdly, biotransformation intermediates of IBU and TCS formed during the application of the biosurfactant and degradation pathways are proposed based on the Liquid Chromatography-Mass Spectrometry (LC-MS) and it indicates that there is no formation of toxic by-products. Based on the results, it is evident that biosurfactant at CMC has performed better for the removal of IBU and TCS than crude biosurfactants without any formation of toxic intermediates. Hence, this study proved to be an eco-friendly, cost-effective and sustainable treatment option for domestic wastewater treatment.

Sophorolipids produced by Yarrowia lipolytica grown on Moringa oleifera oil cake protect against acetic acid-induced colitis in rats: impact on TLR-4/p-JNK/NFκB-p65 pathway

OBJECTIVES

Toll-like receptor-4 (TLR-4) activation plays a major role in triggering oxidative stress (OS) and inflammation implicated in the pathogenesis of ulcerative colitis (UC). Due to sophorolipids (SLs) antioxidant and anti-inflammatory properties, they are interestingly becoming more valued for their potential effectiveness in treating a variety of diseases. This study was designed to explore the effect of SLs produced by microbial conversion of Moringa oleifera oil cake using isolated yeast Yarrowia lipolytica against UC induced by acetic acid (AA) in rats.

METHODS

The produced SLs were identified by FTIR, 1H NMR and LC-MS/MS spectra, and administered orally for 7 days (200 mg/kg/day) before AA (2 ml, 4% v/v) to induce UC intrarectally on day eight. Biochemically, the levels of TLR-4, c-Jun N-terminal kinase (JNK), nuclear factor kappa B-p65 (NFκB-p65), interleukin-1beta (IL-1β), malondialdehyd, glutathione, Bax/Bcl2 ratio and the immunohistochemical evaluation of inducible nitric oxide synthase and caspase-3 were assayed.

KEY FINDINGS

SLs significantly reduced OS, inflammatory and apoptotic markers in AA-treated rats, almost like the reference sulfasalazine.

CONCLUSIONS

This study provided a novel impact for SLs produced by microbial conversion of M. oleifera oil cake against AA-induced UC in rats through hampering the TLR-4/p-JNK/NFκB-p65 signalling pathway.

Bacterial-derived surfactants: an update on general aspects and forthcoming applications

The search for sustainable alternatives to the production of chemicals using renewable substrates and natural processes has been widely encouraged. Microbial surfactants or biosurfactants are surface-active compounds synthesized by fungi, yeasts, and bacteria. Due to their great metabolic versatility, bacteria are the most traditional and well-known microbial surfactant producers, being Bacillus and Pseudomonas species their typical representatives. To be successfully applied in industry, surfactants need to maintain stability under the harsh environmental conditions present in manufacturing processes; thus, the prospection of biosurfactants derived from extremophiles is a promising strategy to the discovery of novel and useful molecules. Bacterial surfactants show interesting properties suitable for a range of applications in the oil industry, food, agriculture, pharmaceuticals, cosmetics, bioremediation, and more recently, nanotechnology. In addition, they can be synthesized using renewable resources as substrates, contributing to the circular economy and sustainability. The article presents a general and updated review of bacterial-derived biosurfactants, focusing on the potential of some groups that are still underexploited, as well as, recent trends and contributions of these versatile biomolecules to circular bioeconomy and nanotechnology.

A comprehensive study on microbial-surfactants from bioproduction scale-up toward electrokinetics remediation of environmental pollutants: Challenges and perspectives

Currently, researchers have focused on electrokinetic (EK) bioremediation due to its potential to remove a wide-range of pollutants. Further, to improve their performance, synthetic surfactants are employed as effective additives because of their excellent solubility and mobility. Synthetic surfactants have an excessive position in industries since they are well-established, cheap, and easily available. Nevertheless, these surfactants have adverse environmental effects and could be detrimental to aquatic and terrestrial life. Owing to social and environmental awareness, there is a rising demand for bio-based surfactants in the global market, from environmental sustainability to public health, because of their excellent surface and interfacial activity, higher and stable emulsifying property, biodegradability, non- or low toxicity, better selectivity and specificity at extreme environmental conditions. Unfortunately, challenges to biosurfactants, like expensive raw materials, low yields, and purification processes, hinder their applicability to large-scale. To date, extensive research has already been conducted for production scale-up using multidisciplinary approaches. However, it is still essential to research and develop high-yielding bacteria for bioproduction through traditional and biotechnological advances to reduce production costs. Herein, this review evaluates the recent progress made on microbial-surfactants for bioproduction scale-up and provides detailed information on traditional and advanced genetic engineering approaches for cost-effective bioproduction. Furthermore, this study emphasized the role of electrokinetic (EK) bioremediation and discussed the application of BioS-mediated EK for various pollutants remediation.

Interdisciplinary Overview of Lipopeptide and Protein-Containing Biosurfactants

Biosurfactants are amphipathic molecules capable of lowering interfacial and superficial tensions. Produced by living organisms, these compounds act the same as chemical surfactants but with a series of improvements, the most notable being biodegradability. Biosurfactants have a wide diversity of categories. Within these, lipopeptides are some of the more abundant and widely known. Protein-containing biosurfactants are much less studied and could be an interesting and valuable alternative. The harsh temperature, pH, and salinity conditions that target organisms can sustain need to be understood for better implementation. Here, we will explore biotechnological applications via lipopeptide and protein-containing biosurfactants. Also, we discuss their natural role and the organisms that produce them, taking a glimpse into the possibilities of research via meta-omics and machine learning.

A Systematic Review on Biosurfactants Contribution to the Transition to a Circular Economy

Since they are more environmentally acceptable than their chemically synthesized counterparts, biosurfactants are used in a wide range of environmental applications. However, less research has been done on biosurfactants within the context of the circular economy, despite their theoretical potential to fulfill a number of circular economy ambitions, including closing the consumption loop, regenerating natural systems, and maintaining resource value within the system. Hence, the main objective of this review is to identify and analyze the contributions of biosurfactants to the implementation of the circular economy. A final sample of 30 papers from the Web of Science database was examined. We identified five broad categories of contributions: waste stream-derived production, combating food waste, strengthening soil health, and improving the efficiency of water resources. We concluded that, while manufacturing biosurfactants from waste streams can reduce production costs, optimizing yield remains a contentious issue that complicates the adoption of biosurfactants into the circular economy framework.

Integrated biorefineries for repurposing of food wastes into value-added products

Food waste (FW) generated through various scenarios from farm to fork causes serious environmental problems when either incinerated or disposed inappropriately. The presence of significant amounts of carbohydrates, proteins, and lipids enable FW to serve as sustainable and renewable feedstock for the biorefineries. Implementation of multiple substrates and product biorefinery as a platform could pursue an immense potential of reducing costs for bio-based process and improving its commercial viability. The review focuses on conversion of surplus FW into range of value-added products including biosurfactants, biopolymers, diols, and bioenergy. The review includes in-depth description of various types of FW, their chemical and nutrient compositions, current valorization techniques and regulations. Further, it describes limitations of FW as feedstock for biorefineries. In the end, review discuss future scope to provide a clear path for sustainable and net-zero carbon biorefineries.

Integration of green economy concepts for sustainable biosurfactant production - A review

The link between increasing global population, food demand, industrialization, and agricultural waste is strong. Decomposing by-products from food cycles can introduce harmful toxic heavy metals, active degrading microbes, and enzymes to the environment. Additionally, high greenhouse gas emissions from the decomposing wastes contribute to global change and a high carbon economy. The bioeconomy and circular economy of biosurfactant production utilize these cheap feedstocks and promote waste to valuable product initiatives. Waste reduction, reuse, and recycling in an integrating green economy bioprocess ensure the sustainability of novel, cost-effective, safe, and renewable health-grade biosurfactants. This work reviews green economy concepts integration with sustainable biosurfactant production and its application in health-related industries. Benefits from recent advances in the production, characterization, and health-wise classification of biosurfactants were further discussed, including its limitations, techno-economic assessment, market evaluations, possible roadblocks, and future directions.

Theranostic efficiency of biosurfactants against COVID-19 and similar viruses - A review

The world has witnessed an extreme vulnerability of a pandemic during 2020; originated from China. The coronavirus disease 2019 (COVID-19) is infecting and beginning deaths in thousands to millions, creating of the global economic crisis. Biosurfactants (BSs) can carry the prevention, control and management of pandemic out through diverse approaches, such as pharmaceutical, therapeutic, hygienic and environmental. The microbiotas having virulent intrinsic properties towards starting as easily as spreading of diseases (huge morbidity and mortality) could be inhibited via BSs. Such elements could be recognised for their antimicrobial activity, capability to interact with the immune system via micelles formation and in nanoparticulate synthesis. However, they can be used for developing novel and more effective therapeutics, pharmaceuticals, non-toxic formulations, vaccines, and effective cleaning agents. Such approaches can be utilized for product development and implemented for managing and combating the pandemic conditions. This review emphasized on the potentiality of BSs as key components with several ways for protecting against unknown and known pathogens, including COVID-19.

Biosurfactants in the sustainable eradication of SARS COV-2 from the environmental surfaces

The COVID-19 outbreak has brought the world, at least, to one consensus that cleanliness is unavoidable under all circumstances. Hands are the main body part to interact with the environment and thus are prone to receive, initiate and propagate the chain of infection. Hand hygiene has, therefore, been most emphasized by experts to interrupt the spread of infection. Various harsh chemicals like synthetic surfactants and alcoholic preparations have been in practice to eradicate and disinfect the germs. This choice may be unsafe and cause a subsequent chain of adversities. Thereby, biosurfactants have been proposed as sustainable, non-toxic and safe surface cleaners cum disinfectants under a wide range of physiological and environmental conditions. The amphiphilic micellar behavior of biosurfactants makes them promising candidates as hygienic surface cleaners and therapeutic carriers. We overview the possibilities of using biosurfactants in different ways against microbial pathogens, in general, and the SARS COV-2, in specific.

Automobile service station waste assessment and promising biological treatment alternatives: a review

Unprecedented growth in the automobile sector has led to an increased number of automobile service stations across all major cities especially in the developing countries. These service stations release huge amounts of waste that contain objectionable levels of oil and grease (O&G) and heavy metals, amongst other environmentally toxic compounds. Not much literature is available on the hazardous nature, public health concerns, and sustainable treatment options of such an industrial waste. This review throws light on the nuisances caused by the automobile industry waste, the various conventional and promising physical-chemical remediation measures adopted, and the scope of bioremediation for the same. Work on the use of microbial enzymes such as lipases and microbial surface-active agents (biosurfactants) as emerging promising candidates for the bioremediation of metals and O&G contaminated automobile service centre wastewater and soil are especially highlighted in this review article. The adoption of constructed wetlands and regular scientific monitoring of service sector are the aspects that would prove to be critical in sustainable and ecological automobile service station waste management. Stricter environment regulations, along with the growing ecological and environmental awareness, call for stringent monitoring of the service station waste and its treatment in an environmentally sustainable manner. This review can effectively aid in revealing potential hazards of this industrial sectors and in policy making for effective environmental monitoring.

Surface-Active Compounds Produced by Microorganisms: Promising Molecules for the Development of Antimicrobial, Anti-Inflammatory, and Healing Agents

Surface-active compounds (SACs), biomolecules produced by bacteria, yeasts, and filamentous fungi, have interesting properties, such as the ability to interact with surfaces as well as hydrophobic or hydrophilic interfaces. Because of their advantages over other compounds, such as biodegradability, low toxicity, antimicrobial, and healing properties, SACs are attractive targets for research in various applications in medicine. As a result, a growing number of properties related to SAC production have been the subject of scientific research during the past decade, searching for potential future applications in biomedical, pharmaceutical, and therapeutic fields. This review aims to provide a comprehensive understanding of the potential of biosurfactants and emulsifiers as antimicrobials, modulators of virulence factors, anticancer agents, and wound healing agents in the field of biotechnology and biomedicine, to meet the increasing demand for safer medical and pharmacological therapies.

Biological and Cosmetical Importance of Fermented Raw Materials: An Overview

The cosmetics industry is currently looking for innovative ingredients with higher bioactivity and bioavailability for the masses of natural and organic cosmetics. Bioferments are innovative ingredients extracted from natural raw materials by carrying out a fermentation process with appropriate strains of microorganisms. The review was conducted using the SciFinder database with the keywords “fermented plant”, “cosmetics”, and “fermentation”. Mainly bioferments are made from plant-based raw materials. The review covers a wide range of fermented raw materials, from waste materials (whey with beet pulp) to plant oils (F-Shiunko, F-Artemisia, F-Glycyrrhiza). The spectrum of applications for bioferments is broad and includes properties such as skin whitening, antioxidant properties (blackberry, soybean, goji berry), anti-aging (red ginseng, black ginseng, Citrus unshiu peel), hydrating, and anti-allergic (aloe vera, skimmed milk). Fermentation increases the biochemical and physiological activity of the substrate by converting high-molecular compounds into low-molecular structures, making fermented raw materials more compatible compared to unfermented raw materials.

Lipopeptide surfactin ameliorates the cell uptake of platensimycin and enhances its therapeutic effect on treatment of MRSA skin infection

OBJECTIVES

The rapid development of drug-resistant bacteria, especially MRSA, poses severe threats to global public health. Adoption of antibiotic adjuvants has proved to be one of the efficient ways to solve such a crisis. Platensimycin and surfactin were comprehensively studied to combat prevalent MRSA skin infection.

METHODS

MICs of platensimycin, surfactin or their combinations were determined by resazurin assay, while the corresponding MBCs were determined by chequerboard assay. Growth inhibition curves and biofilm inhibition were determined by OD measurements. Membrane permeability analysis was conducted by propidium iodide staining, and morphological characterizations were performed by scanning electron microscopy. Finally, the therapeutic effects on MRSA skin infections were evaluated in scald-model mice.

RESULTS

The in vitro assays indicated that surfactin could significantly improve the antibacterial performance of platensimycin against MRSA, especially the bactericidal activity. Subsequent mechanistic studies revealed that surfactin not only interfered with the biofilm formation of MRSA, but also disturbed their cell membranes to enhance membrane permeability, and therefore synergistically ameliorated MRSA cellular uptake of platensimycin. Further in vivo assessment validated the synergistic effect of surfactin on platensimycin and the resultant enhancement of therapeutical efficacy in MRSA skin-infected mice.

CONCLUSIONS

The combination of effective and biosafe surfactin and platensimycin could be a promising and efficient treatment for MRSA skin infection, which could provide a feasible solution to combat the major global health threats caused by MRSA.

Biocatalytic lipoprotein bioamphiphile induced treatment of recalcitrant hydrocarbons in petroleum refinery oil sludge through transposon technology

The present investigation employed transposon technology to enhance the degradation of recalcitrant petroleum hydrocarbons present in petroleum oil sludge by using biosurfactant hyper-producing strain Enterobacter xiangfangensis STP-3. Out of 2500 transposon induced mutants, mutants M_{257E.xiangfangensis} and M_{916E.xiangfangensis} hyper-produce biocatalytic lipoprotein biosurfactant by1.98 and 2.34 fold higher than wild-type strain. Transposon induced mutation also modified the amino acid composition which improved the hydrophobicity and thermal stability of the biosurfactants produced by mutants, compared to the wild-type biosurfactant. GC-MS and LC-MS-MS revealed that biosurfactants have pentameric lipid moiety and esterase as protein moiety. Increased biosurfactant hydrophobicity and yield by the mutants resulted in the enhanced bioavailability of petroleum hydrocarbons, thereby mutants M_{257E.xiangfangensis} and M_{916E.xiangfangensis} demonstrated better petroleum oil sludge degradation by 82% and 88% respectively, than wild-type (72%). Disrupted genes vgr G and pgm M in M257_{E.xiangfangensis} and M916_{E.xiangfangensis} respectively hyper-produce biosurfactant by competitive pathway inhibition and increased precursor availability mechanism. Hyper-production of biosurfactant was also validated by comparing the expression of biosynthetic genes ent E, ent F and est using qPCR. This is the first report on the application of transposon technology to hyper-produce biosurfactant for the effective bioremediation of hydrocarbon contaminated environments.

Bioinspired Rhamnolipid Protects Wheat Against Zymoseptoria tritici Through Mainly Direct Antifungal Activity and Without Major Impact on Leaf Physiology

Rhamnolipids (RLs), glycolipids biosynthesized by the Pseudomonas and Burkholderia genera, are known to display various activities against a wide range of pathogens. Most previous studies on RLs focused on their direct antimicrobial activity, while only a few reports described the mechanisms by which RLs induce resistance against phytopathogens and the related fitness cost on plant physiology. Here, we combined transcriptomic and metabolomic approaches to unravel the mechanisms underlying RL-induced resistance in wheat against the hemibiotrophic fungus Zymoseptoria tritici, a major pathogen of this crop. Investigations were carried out by treating wheat plants with a bioinspired synthetic mono-RL with a 12-carbon fatty acid tail, dodecanoyl α/β-L-rhamnopyranoside (Rh-Est-C12), under both infectious and non-infectious conditions to examine its potential wheat defense-eliciting and priming bioactivities. Whereas, Rh-Est-C12 conferred to wheat a significant protection against Z. tritici (41% disease severity reduction), only a slight effect of this RL on wheat leaf gene expression and metabolite accumulation was observed. A subset of 24 differentially expressed genes (DEGs) and 11 differentially accumulated metabolites (DAMs) was scored in elicitation modalities 2, 5, and 15 days post-treatment (dpt), and 25 DEGs and 17 DAMs were recorded in priming modalities 5 and 15 dpt. Most changes were down-regulations, and only a few DEGs and DAMs associated with resistance to pathogens were identified. Nevertheless, a transient early regulation in gene expression was highlighted at 2 dpt (e.g., genes involved in signaling, transcription, translation, cell-wall structure, and function), suggesting a perception of the RL by the plant upon treatment. Further in vitro and in planta bioassays showed that Rh-Est-C12 displays a significant direct antimicrobial activity toward Z. tritici. Taken together, our results suggest that Rh-Est-C12 confers protection to wheat against Z. tritici through direct antifungal activity and, to a lesser extent, by induction of plant defenses without causing major alterations in plant metabolism. This study provides new insights into the modes of action of RLs on the wheat-Z. tritici pathosystem and highlights the potential interest in Rh-Est-C12, a low-fitness cost molecule, to control this pathogen.

Characterization of a potent biosurfactant produced from Franconibacter sp. IITDAS19 and its application in enhanced oil recovery

Biosurfactants are surface-active molecules produced from microorganisms either on the cell surface or secreted extracellularly. Several biosurfactant producing microorganisms have been isolated to date, but they differ in their efficacy towards different types of hydrocarbons. Here, we report the isolation and characterization of a biosurfactant producing bacterium Franconibacter sp. IITDAS19 from crude oil contaminated soil. The biosurfactant was isolated, purified and characterized. It was identified as a glycolipid. It was found to be very stable at wide range of temperatures, pH and salt concentrations. It could reduce the surface tension of the water from 71 mN/m to 31 mN/m. IITDAS19 showed very high efficacy towards both aliphatic and aromatic hydrocarbons. It resulted in about 63% recovery of residual oil in a sand pack column. Our results suggested that the produced biosurfactant can be used for enhanced oil recovery. To our knowledge, this is the first report demonstrating the detailed characterization of a biosurfactant from Franconibacter spp.

Isolation and chemical characterization of the biosurfactant produced by Gordonia sp. IITR100

Biosurfactants are amphipathic molecules produced from microorganisms. There are relatively few species known where the detailed chemical characterization of biosurfactant has been reported. Here, we report isolation and chemical characterization of the biosurfactant produced by a biodesulfurizing bacterium Gordonia sp. IITR100. Biosurfactant production was determined by performing oil spreading, drop-collapse, Emulsion index (E24), and Bacterial adhesion to hydrocarbons (BATH) assay. The biosurfactant was identified as a glycolipid by LCMS and GCMS analysis. The chemical structure was further confirmed by performing FTIR and NMR of the extracted biosurfactant. The emulsion formed by the biosurfactant was found to be stable between temperatures of 4°C to 30°C, pH of 6 to 10 and salt concentrations up to 2%. It was successful in reducing the surface tension of the aqueous media from 61.06 mN/m to 36.82 mN/m. The biosurfactant produced can be used in petroleum, detergents, soaps, the food and beverage industry and the healthcare industry.