Pesticide pollution remains a significant environmental challenge, necessitating the exploration of sustainable alternatives. Biosurfactants are a class of unconventional surface-active chemicals that are produced by microorganisms. Biosurfactants have many applications in treating oil spills, emulsifiers, pharmaceuticals, and agriculture. Compared to chemical surfactants, they have benefits such as biodegradability, less toxicity, and a greener option because they are derived from microbes. Biosurfactants have recently been shown to have the potential to speed up pesticide cleanup. Biosurfactants are used in pesticide remediation because of their exceptional foaming ability, high selectivity, and wide range of pH, salinity, and temperature operating windows. Microbial biosurfactants emerged as potential agents for the treatment of organic waste and agricultural residue. This review unfolds the promising realm of microbial biosurfactants as green solutions for environmental sustainability, particularly in agricultural practices, with special reference to pesticide remediation. This article highlights the escalating need for eco-friendly alternatives, paving the way for discussing biosurfactants. Moreover, the articles discuss in detail various advancements in the field of rapid screening of biosurfactants, either using a conventional approach or via advanced instruments such as GC-MS, HPLC, NMR, FTIR, etc. Furthermore, the article unveils the molecular mechanisms and the microbial genes driving biosurfactant synthesis, offering insights into enhancing production efficiency. Moreover, the article explores diverse applications of microbial biosurfactants in sustainable agriculture, ranging from soil remediation to crop protection. The article also highlights the various functions of microbial biosurfactants for enhancing the decomposition and recycling of organic waste and agricultural residues, emphasizing their potential for sustainable waste management strategies. Overall, the review underscores the pivotal role of microbial biosurfactants as green alternatives for addressing pesticide pollution and advancing environmental sustainability.

Surfactants are amphiphilic substances that induce surface tension reduction, washing, and emulsification and are used for various purposes. Recently, biosurfactants manufactured from renewable resources and with high biocompatibility have gained increasing attention. Sophorolipid (SL), a type of biosurfactant derived from Starmerella bombicola, possesses detergency and emulsification properties, making it suitable for household and personal care applications. However, there are limited toxicological data on SLs. In this study, we conducted cytotoxicity and skin-irritation tests using SLs, revealing that cytotoxicity and skin irritation induced by SLs were extremely low (logIC 50 = 4.76 mg/L) and equivalent to those of solvents and oils used in personal care products.

The use of natural and sustainable additives, that are less aggressive to the environment, is a trend in the food industry. Rhamnolipids (RL) biosurfactants have shown potential for controlling food pathogens however, due to the presence of free carboxyl groups, the pH and ionic strength may influence the properties of such surfactants. In this study, we describe the antimicrobial activity of RL under different pH values and NaCl concentrations, towards both planktonic and biofilms of Listeria monocytogenes. RL were effective at pH 5.0 and the addition of 5 % NaCl improved the bactericidal efficacy for planktonic and sessile cells. The effect of NaCl was more pronounced at pH above 6 showing a significant increase in RL antimicrobial activity. At pH 7.0 planktonic population was eradicated by RL only when salt was present whereas biofilm viability was decreased by 5 log with MBIC varying from > 2500.0 mg/L (RL) to 39.0 mg/L (RL + 5 % NaCl). Larger vesicular and lamellar RL self-assembly structures were predominant when NaCl was present, suggesting their association with the antimicrobial activity observed. The pH and ionic strength of the medium are important parameters to be considered for the development of RL-based strategies to control L. monocytogenes.

Particulate matter (PM) is one of the most hazardous atmospheric pollutants. Several plant species show high potential to reduce air pollutants and are widely used as green belts to provide clean outdoor spaces for human well-being. However, high PM concentrations cause physiological changes and stress in plants. In this study, 11 species of Thai native perennial plants were exposed to PM generated from tobacco smoke. Wrightia religiosa (Teijsm. & Binn.) Benth. ex Kurz, Bauhinia purpurea DC. ex Walp. and Tectona grandis L.f. reduced PM effectively (which is in the typical range of 43.95 to 52.97%) compared to other plant species. In addition, the responses of perennial plants under PM stress at the proteomic level were also evaluated. Proteomic analysis of these three plant species showed that plants respond negatively to high PM concentrations, such as reducing several photosynthetic-related proteins and increasing plant stress response proteins. To improve PM phytoremediation efficiency and reduce plant stress from PM, perennial plant-microbe interactions were investigated. W. religiosa was inoculated with Acinetobacter indicus PS1, and high biosurfactant-producing strains clearly showed a higher PM removal efficiency than non-inoculated plants (9.48, 9.5 and 12.6% for PM1.0, PM2.5 and PM10, respectively). Inoculating W. religiosa with A. indicus PS1 maintained chlorophyll a and b concentrations. Moreover, the malondialdehyde (MDA) concentration of W. religiosa inoculated with A. indicus PS1 was lower than that of non-inoculated W. religiosa. The leaf wax content (µg/cm2) and biosurfactant (µg/cm2) of W. religiosa inoculated with A. indicus PS1 were also higher than those of non-inoculated W. religiosa. This study clearly showed that inoculating plants with A. indicus PS1 can help plants remediate PM and improve their PM stress response.

Excessive usage of biologically toxic fungicides and their matrix materials poses a serious threat to public health. Leveraging fungicide carriers with inherent pathogen inhibition properties is highly promising for enhancing fungicide efficacy and reducing required dosage. Herein, a series of coacervates have been crafted with lignin and surfactin, both of which are naturally derived and demonstrate substantial antifungal properties. This hierarchically assembled carrier not only effectively loads fungicides with a maximum encapsulation efficiency of 95% but also stably deposits on hydrophobic leaves for high-speed impacting droplets. Intriguingly, these coacervates exhibit broad spectrum fungicidal activity against eight ubiquitous phytopathogens and even act as a standalone biofungicide to replace fungicides. This performance can significantly reduce the fungicide usage and be further strengthened by an encapsulated fungicide. The inhibition rate reaches 87.0% when 0.30 mM pyraclostrobin (Pyr) is encapsulated within this coacervate, comparable to the effectiveness of 0.80 mM Pyr alone. Additionally, the preventive effects against tomato gray mold reached 53%, significantly surpassing those of commercial adjuvants. Thus, it demonstrates that utilizing biosurfactants and biomass with intrinsic antifungal activity to fabricate fully biobased coacervates can synergistically combine the functions of a fungicide carrier and antifungal agent against phytopathogens and guarantee environmental friendliness. This pioneering approach provides deeper insights into synergistically enhancing the effectiveness of agrochemicals from multiple aspects, including fungicide encapsulation, cooperative antifungal action, and droplet deposition.

This study employs Taguchi design of experiments (DOE) to optimize biosurfactant yield by analyzing the impact of various input parameters. Signal-to-noise ratio analysis was utilized for optimization, corroborated by ANOVA findings. Regression equations depicted response behaviour and are validated through a confirmation test. Taguchi methodology identified optimal conditions for maximum biosurfactant yield: agitation (180 rpm), inoculum size (2%), beef extract (5 g/L), diesel (20 ml/L), peptone (5 g/L), NaCl (7 g/L), incubation time (4 days), pH (7.9), and yeast extract (6 g/L). This yielded an 8.33% increase to 1.53 g/L, with initial optimum parameters projecting 1.41 g/L. ANOVA ranked and quantified control factor contributions, revealing agitation\'s significant (31.41%) impact on yield. The study underscores the viability of Taguchi\'s optimal conditions for substantial yield improvement within specific ranges. The strong alignment between expected and experimental yields affirmed the reliability of developed models for optimal yield selection. This study underscores the power of statistical techniques like Taguchi DOE and ANOVA in systematically enhancing biosurfactant production by Bacillus aryabhattai SPS1001 and paves the way for future advancements in bioprocess optimization.

Acne affects most of the world\'s population, causing an impact on the self-esteem of adolescents and young adults. One of the causes is the presence of the bacteria Cutibacterium acnes which are part of the natural microbiota of the skin. Topical treatments consist of anti-inflammatory and antibiotics, which could select resistant strains. Alternatives to the antibiotic are biocomposites that have antimicrobial activity like biosurfactants which are produced by bacteria. An innovative way of applying these compounds is bioadhesive polymeric films that adhere to the skin and release the active principle topically. Rhamnolipids have great potential to be used in the treatment of acne because they present antimicrobial activity against C. acnes in low and safe concentrations (MIC of 15.62 µg/mL, CBM of 31.25 µg/mL and CC50 of 181.93 µg/mL). Four films with different rhamnolipids concentrations (0.0; 0.1; 0.2; and 0.3%, w/w) were obtained as to visual appearance, mass variation, thickness, density, solubility, pH, water vapor transmission, mechanical properties (folding endurance, bioadhesion strength, tensile strength, elongation at break and Young\'s modulus), scanning electron microscopy and infrared. The results show that these formulations had a homogeneous appearance; elastic mechanical properties; pH similar to human skin and bioadhesive. The polymeric films containing rhamnolipids were effective against C. acnes, in the in vitro test, at the three concentrations tested, the film with the highest concentration (0.3%, w/w) being the most promising for presenting the highest antimicrobial activity. Thus, the polymeric film containing rhamnolipids has the potential to be used in the treatment of acne.

Surfactants are amphiphilic molecules that are capable of mixing water and oil. Biosurfactants are eco-friendly, low-toxicity, and stable to a variety of environmental factors. Optimizing conditions for microorganisms to produce biosurfactants can lead to improved production suitable for scaling up. In this study, we compared heterologous expression levels of the luminescence system luxCDABE operon controlled by regulatable promoters araC-PBAD and its strong version araC-PBAD-SD in Escherichia coli K12, Pseudomonas aeruginosa PAO1, and P. putida KT2440. Real-time monitoring of luminescence levels in the three strains indicated that luxCDABE controlled by araC-PBAD-SD promoter with 0.2% arabinose supplementation in P. putida produced the highest level of luminescence. By using the araC-PBAD-SD promoter-controlled rhlAB expression in P. putida, we were able to produce mono-rhamnolipid at a level of 1.5 g L-1 when 0.02% arabinose was supplemented. With the same system to express olsB, lyso-ornithine lipid was produced at a level of 10 mg L-1 when 0.2% arabinose was supplemented. To our knowledge, this is the first report about optimizing conditions for lyso-ornithine lipid production at a level up to 10 mg L-1. Taken together, our results demonstrate that regulatable araC-PBAD-SD promoter in P. putida KT2440 is a useful system for heterologous production of biosurfactants.

Byproducts and wastes from the food processing industry represent an important group of wastes generated annually in large quantities. It is important to note that the amount of this waste will increase with industrialization, and effective solutions must be found urgently. Many wastes that cause environmental pollution are evaluated by their low-tech conversion into products with little economic value, such as animal feed and fertilizer. Therefore, the evaluation of food processing waste using effective recycling techniques has become an interesting subject with increasing population, ongoing biotechnological studies, and advances in technology. The conversion of food waste into biotechnological products via fermentation is a sustainable, environmentally friendly, and economical method in line with the principles of green chemistry. This approach promotes the reuse of food waste by supporting the principles of a circular economy and offers sustainable alternatives to fossil fuels and synthetic chemicals. This contributes to reducing the carbon footprint, preserving soil and water quality, and providing economic sustainability through the production of high-value products. In this study, the properties of olive mill wastewater, an important and valuable waste in the olive oil industry, its environmental aspects, and its use in biotechnological applications that integrate green chemistry are evaluated.

Liamocins are molecules with a polyol lipid structure produced by rare strains of Aureobasidium pullulans. In recent years, liamocins have attracted attention due to their antibacterial, anticancer and surface-active properties, and promising potential applications have been identified in the food, agriculture, medical and pharmaceutical industries. This study is the first to investigate the effects of different carbon and nitrogen sources on the growth and liamocin production kinetics of A. pullulans NBRC 100716 strain. This strain was selected among six different A. pullulans strains whose liamocin productions were tested by us for the first time. In fermentations carried out in shaking water baths, the carbon source that most supported the liamocin production of this strain was fructose, and the nitrogen source was peptone-yeast extract combination. In the medium containing fructose and the peptone-yeast extract mixture, A. pullulans NBRC 100716 produced 4.26 g liamocin L-1. The specific liamocin production rate (qp) of the strain in this medium was 0.0090 g liamocin/g mo.h. This study is also the first to produce liamocin with a fructophilic A. pullulans strain. Present findings in this research also demonstrated the excellent biosurfactant capacity of the liamocin produced by this strain. The obtained liamocin reduced the water surface tension to a degree that can compete with synthetic surfactants. Furthermore, this is the first report to reveal that the fatty acid profile of liamocin obtained from A. pullulans NBRC 100716 contains an appreciable amount of unsaturated fatty acids and is similar to the composition of vegetable oil.