Sophorolipid Biosurfactant Can Control Cutaneous Dermatophytosis Caused by Trichophyton mentagrophytes

Interaction between Sophorolipids and β-glucan in Aqueous Solutions

Skin disorders, including acne vulgaris, atopic dermatitis, and rosacea, are characterized by the presence of biofilms, which are communities of microorganisms. The mechanical stability of biofilms is attributed to one of their constituents-polysaccharides-which are secreted by microorganisms. Sophorolipids are biosurfactants with biofilm disruption and removal abilities and are expected to become alternatives for classical petrochemical-based surfactants in cosmetics. In this study, we investigated the influence of sophorolipids on β-glucan such as dispersion status, interaction mechanism, and configuration change as a model polysaccharide of biofilm in aqueous solution. Dynamic light scattering measurements showed that sophorolipids interfere with the aggregation of β- glucan in aqueous solutions. In contrast, sodium dodecyl sulfate (SDS), which is used as a typical surfactant reference, promotes the aggregation of β-glucan. The interaction between sophorolipids and β-glucan were investigated using surface tension measurements and isothermal titration calorimetry (ITC). Surface tension increased only near critical micelle concentration (CMC) region of sophorolipids in the presence of β-glucan. This suggests that the interaction occurred in the solution rather than at the air-liquid interface. Moreover, the results of ITC indicate that hydrophobic interactions were involved in this interaction. In addition, the results of optical rotation measurements indicate that sophorolipids did not unfold the triple helical structure of β-glucan. β-glucan dispersion was expected to be caused steric hindrance and electrostatic repulsion when sophorolipids interacted with β-glucan via hydrophobic interactions owing to the unique molecular structure of sophorolipids attributed by a bulky sugar moiety and a carboxyl functional group. These results demonstrated unique performances of sophorolipids on β-glucan and provided more insights on the efficacy of sophorolipids as good anti-biofilms.

Synergistic antifungal activity and potential mechanism of action of a glycolipid-like compound produced by Streptomyces blastmyceticus S108 against Candida clinical isolates

AIM

The present study aimed to investigate a novel antifungal compound produced by Streptomyces blastmyceticus S108 strain. Its effectiveness against clinical isolates of Candida species and its synergistic effect with conventional antifungal drugs were assessed, and its molecular mechanism of action was further studied against Candida albicans.

METHODS AND RESULTS

A newly isolated strain from Tunisian soil, S. blastmyceticus S108, showed significant antifungal activity against Candida species by well diffusion method. The butanolic extract of S108 strain supernatant exhibited the best anti-Candida activity with a minimal inhibitory concentration (MIC) value of 250 μg ml-1, determined by the microdilution method. The bio-guided purification steps of the butanolic extract were performed by chromatographic techniques. Among the fractions obtained, F13 demonstrated the highest level of activity, displaying a MIC of 31.25 μg ml-1. Gas chromatography-mass spectrometry and electrospray ionization mass spectrometry analyses of this fraction (F13) revealed the glycolipidic nature of the active molecule with a molecular weight of 685.6 m/z. This antifungal metabolite remained stable to physicochemical changes and did not show hemolytic activity even at 4MIC corresponding to 125 µg ml-1 toward human erythrocytes. Besides, the glycolipid compound was combined with 5-flucytosine and showed a high synergistic effect with a fractional inhibitory concentration index value 0.14 against C. albicans ATCC 10231. This combination resulted in a decrease of MIC values of 5-flucytosine and the glycolipid-like compound by 8- and 64-fold, respectively. The examination of gene expression in treated C. albicans cells by quantitative polymerase chain reaction (qPCR) revealed that the active compound tested alone or in combination with 5-flucytosine blocks the ergosterol biosynthesis pathway by downregulating the expression of ERG1, ERG3, ERG5, ERG11, and ERG25 genes.

CONCLUSION AND IMPACT OF THE STUDY

The new glycolipid-like compound, produced by Streptomyces S108 isolate, could be a promising drug for medical use against pathogenic Candida isolates.

Lipopeptides development in cosmetics and pharmaceutical applications: A comprehensive review

Lipopeptides are surface active, natural products of bacteria, fungi and green-blue algae origin, having diverse structures and functionalities. In analogy, a number of chemical synthesis techniques generated new designer lipopeptides with desirable features and functions. Lipopetides are self-assembly guided, supramolecular compounds which have the capacity of high-density presentation of the functional epitopes at the surface of the nanostructures. This feature contributes to their successful application in several industry sectors, including food, feed, personal care, and pharmaceutics. In this comprehensive review, the novel class of ribosomally synthesized lipopeptides is introduced alongside the more commonly occuring non-ribosomal lipopeptides. We highlight key representatives of the most researched as well as recently described lipopeptide families, with emphasis on structural features, self-assembly and associated functions. The common biological, chemical and hybrid production routes of lipopeptides, including prominent analogues and derivatives are also discussed. Furthermore, genetic engineering strategies aimed at increasing lipopeptide yields, diversity and biological activity are summarized and exemplified. With respect to application, this work mainly details the potential of lipopeptides in personal care and cosmetics industry as cleansing agents, moisturizer, anti-aging/anti-wrinkling, skin whitening and preservative agents as well as the pharmaceutical industry as anitimicrobial agents, vaccines, immunotherapy, and cancer drugs. Given that this review addresses human applications, we conclude on the topic of safety of lipopeptide formulations and their sustainable production.

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.

Review on sophorolipids – a promising microbial bio-surfactant

Surfactants are amphiphilic molecules used primarily for cleaning. Petroleum-based surfactants have a high production rate, but are non-biodegradable and destructive to the environment. Environmentally friendly biosurfactants are therefore becoming increasingly important. In addition to not being toxic; they are environmentally safe and mild to the skin. Depending on their structure, there are different types of biosurfactants. One of the types are the glycolipids, they are low molecular weight biosurfactants, and consist of sophorolipids. Sophorolipids are getting more attention as alternative to petroleum-based surfactants due to excellent stability at various pH levels, temperatures, and salinities. In addition to being anti-microbial, they have excellent wetting and foaming abilities and act as emulsifiers. There are numerous applications of sophorolipids in food, agriculture, biomedicine, cosmetics and personal care.

Dermatophytic Biofilms: Characteristics, Significance and Treatment Approaches

Microbes are found in the environment, possibly more often as biofilms than in planktonic forms. Biofilm formation has been described for several important fungal species. The presence of a dermatophytoma in a dermatophytic nail infection was the basis for the proposal that dermatophytes form biofilms as well. This could explain treatment failure and recurrent dermatophytic infections. Several investigators have performed in vitro and ex vivo experiments to study the formation of biofilms by dermatophytes and their properties. The nature of the biofilm structure itself contributes to fungal protection mechanisms against many harmful external agents, including antifungals. Thus, a different approach should be carried out regarding susceptibility testing and treatment. Concerning susceptibility testing, methods to evaluate either the inhibition of biofilm formation, or the ability to eradicate it, have been introduced. As for treatment, in addition to classical antifungal agents, some natural formulations, such as plant extracts or biosurfactants, and alternative approaches, such as photodynamic therapy, have been proposed. Studies that connect the results of the in vitro and ex vivo experimentation with clinical outcomes are required in order to verify the efficacy of these approaches in clinical practice.

Pharmaceutical prospects of biosurfactants produced from fungal species

The development of novel types of biogenic surface-active compounds is of greater interest for combating many diseases and infections. In this respect research and development of biosurfactant has gained immense importance. Substantially, biosurfactant is defined as a class of active amphiphilic chemical compounds that comprise hydrophobic and hydrophilic moieties on their surfaces. It is generally known that many kinds of microorganisms can be used to produce these surfactants or surface-active compounds. Hosting interesting features such as biodegradability, emulsifying/de-emulsifying capacity, low toxicity, and antimicrobial activities; these amphiphilic compounds in recent years have flourished as an ideal replacement for the chemically synthesized surfactant, and also have various commercial attractions. Both bacteria and fungi are the producers of these amphiphilic molecules; however, the pathogenicity of certain bacterial strains has caused a shift in interest toward fungi. Therefore, various fungi species have been reported for the production of biosurfactants amongst which Candida species have been the most studied strains. Biosurfactants uphold desired properties like antibacterial, antifungal, antiviral, antiadhesion, and anticancer activity which proves them an ideal candidate for the application in various fields like pharmaceutical, gene therapy, medical insertion safety, immunotherapy to fight against many chronic diseases, and so forth. Hence, this review article discusses the pharmaceutical prospects of biosurfactants produced from different fungal species, providing new directions toward the discovery and development of molecules with novel structures and diverse functions for advanced application in the medical field.

Sophorolipids—Bio-Based Antimicrobial Formulating Agents for Applications in Food and Health

Sophorolipids are well-known glycolipid biosurfactants, produced mainly by non-pathogenic yeast species such as Candida bombicola with high yield. Its unique environmental compatibility and high biodegradable properties have made them a focus in the present review for their promising applications in diverse areas. This study aims to examine current research trends of sophorolipids and evaluate their applications in food and health. A literature search was conducted using different research databases including PubMed, ScienceDirect, EBSCOhost, and Wiley Online Library to identify studies on the fundamental mechanisms of sophorolipids and their applications in food and health. Studies have shown that various structural forms of sophorolipids exhibit different biological and physicochemical properties. Sophorolipids represent one of the most attractive biosurfactants in the industry due to their antimicrobial action against both Gram-positive and Gram-negative microorganisms for applications in food and health sectors. In this review, we have provided an overview on the fundamental properties of sophorolipids and detailed analysis of their applications in diverse areas such as food, agriculture, pharmaceutical, cosmetic, anticancer, and antimicrobial activities.

Production of new antimicrobial palm oil-derived sophorolipids by the yeast Starmerella riodocensis sp. nov. against Candida albicans hyphal and biofilm formation

BACKGROUND

Microbial derived-surfactants display low eco-toxicity, diverse functionality, high biodegradability, high specificity, and stability under extreme conditions. Sophorolipids are emerging as key biosurfactants of yeast origins, used in various industrial sectors to lower surface tension. Recently, sophorolipid complexes have been applied in biomedicals and agriculture to eradicate infectious problems related to human and plant fungal pathogens. This study aimed to characterize the functional properties and antifungal activities of sophorolipids produced by a newly characterized Starmerella riodocensis GT-SL1R sp. nov. strain.

RESULTS

Starmerella riodocensis GT-SL1R sp. nov. strain was belonged to Starmerella clade with 93.12% sequence similarity using the ITS technique for strain identification. Sophorolipids production was examined, using co-carbon substrates glucose and palm oil, with a yield on the substrate between 30 and 46%. Using shake-flasks, the S. riodocensis GT-SL1R strain produced biosurfactants with an emulsification activity of 54.59% against kerosene compared to the S. bombicola BCC5426 strain with an activity of 60.22%. Maximum productivities of GT-SL1R and the major sophorolipid-producer S. bombicola were similar at 0.8 gl^-1 h^-1. S. riodocensis GT-SL1R produced mixed forms of lactonic and acidic sophorolipids, shown by TCL, FTIR, and HPLC. Importantly, the complex sophorolipid mixture displayed antifungal activity against an opportunistic yeast pathogen Candida albicans by effectively reducing hyphal and biofilm formation.

CONCLUSIONS

Sophorolipids derived from S. riodocensis demonstrate potential industrial and biomedical applications as green surfactant and antifungal agent. Since numerous renewable bioresources and industrial wastes could be used by microbial cell factories in the biosynthesis of biosurfactants to reduce the production cost, sophorolipids hold a promising alternative to current antimicrobials in treatments against infectious diseases in humans, animals, and plants.

Mannosylerythritol lipids: production, downstream processing, and potential applications

Mannosylerythritol lipids (MELs) are biosurfactants produced by various fungal species. Depending on the degree of acetylation and further chemical modifications, these glycolipids can show remarkable biological properties, including the increase of water retention in the stratum corneum suppression of melanogenic enzymes tyrosinase-1 and -2, reversion of UV-A radiation-induced aquaporin-3 suppression, skin whitening, and anti-aging effects. These applications of MELs require high purity, which is usually reached by liquid-liquid extraction followed by chromatography, obtaining ≥95% purity. This worked aimed to critically discuss the current state of the art and trends on the production of MELs, including post-production treatment as enzymatic conversion. In addition, their application as skincare or pharmaceutical agents and agricultural biostimulants.

Dendrobium officinale Endophytes May Colonize the Intestinal Tract and Regulate Gut Microbiota in Mice

Dendrobium officinale is a traditional Chinese medicine for treating gastrointestinal diseases by nourishing “Yin” and thickening the stomach lining. To study whether D. officinale endophytes can colonize the intestinal tract and regulate gut microbiota in mice, we used autoclave steam sterilizing and 60Co-γ radiation to eliminate D. officinale endophytes from its juice. Then, high-throughput ITS1-ITS2 rDNA and 16S rRNA gene amplicons were sequenced to analyze the microbial community of D. officinale endophytes and fecal samples of mice after administration of fresh D. officinale juice. Sterilization of D. officinale juice by autoclaving for 40 min (ASDO40) could more effectively eliminate the D. officinale endophytes and decrease their interference on the gut microbiota. D. officinale juice could increase beneficial gut microbiota and metabolites including short-chain fatty acids. D. officinale endophytes Pseudomonas mosselii, Trichocladium asperum, Titata maxilliformis, Clonostachys epichloe, and Rhodotorula babjevae could colonize the intestinal tract of mice and modulate gut microbiota after oral administration of the juice for 28 days. Thus, the regulatory effect of D. officinale juice on gut microbiota was observed, which provides a basis for inferring that D. officinale endophytes might colonize the intestinal tract and participate in regulating gut microbiota to treat diseases. Thus, this study further provides a new approach for the treatment of diseases by colonizing plant endophytes in the intestinal tract and regulating gut microbiota.

Quantitative analysis of in vitro biofilm formation by clinical isolates of dermatophyte and antibiofilm activity of common antifungal drugs

BACKGROUND

The ability of dermatophytes to develop biofilm, as one of the virulence factors in fungal infections which contribute to antifungal resistance, is an outstanding aspect of dermatophytosis that has been noted recently. Because of the paucity of data about the biofilm formation by dermatophytes and their susceptibility to antifungal drugs, this study evaluated the biofilm formation by clinical isolates of dermatophytes and antibiofilm activity of common antifungals widely used to manage dermatophytosis.

METHODS

The ribosomal DNA internal transcribed spacer (ITS) regions sequencing for species identification of 50 clinical dermatophyte isolates was performed. The ability of isolates to form biofilm and inhibitory activity of itraconazole, terbinafine, and griseofulvin against biofilm formation was assayed by the crystal violet staining method. Optical microscopy and scanning electron microscopy (SEM) were applied for the visualization of the biofilm structures.

RESULTS

Trichophyton (T.) mentagrophytes (n: 14; 28%) and T. rubrum (n: 13;26%) were included in more than half of the dermatophyte isolates. Biofilm formation was observed in 37 out of 50 (74%) isolates that were classified as follows: nonproducers (n: 13; 26%), weak producers (n: 4; 8%), moderate producers (n: 16; 32%), and strong producers (n: 17; 34%) by comparison of the absorbance of biofilms produced by clinical strains with control. The mean IC50 values for terbinafine, griseofulvin, and itraconazole were 2.42, 3.18, and 3.78 μg/ml, respectively.

CONCLUSIONS

The results demonstrated that most of the clinical dermatophyte isolates are capable to form biofilm in vitro with variable strength. Moreover, terbinafine can be suggested as the first-line choice for the treatment of biofilm-formed dermatophytosis.

Removal of a Model Biofilm by Sophorolipid Solutions: A QCM-D Study

Biofilms are communities of microorganisms that have been widely studied because they can cause hospital-acquired infections and skin disorders. Polysaccharides secreted by microorganisms are constituents of biofilms, contributing to their adhesion and mechanical stability. Sophorolipids are biosurfactants with the ability to disrupt and remove biofilms. Biosurfactants have been targeted as potential substitutes for classical petrochemical-based surfactants in cosmetics. In this study, we fabricate a β-glucan film as a model biofilm, and quartz crystal microbalance with dissipation monitoring (QCM-D) measurements are used to assess the biofilm removal. The viscoelasticity of the β-glucan films is monitored while sophorolipid solutions are introduced into the system, and we found that the film removal performance increases with the sophorolipid concentration. In addition, Δf (change in frequency)-ΔD (change in energy dissipation) plot analyses reveal that two processes are involved in the removal mechanism. The first process involves the adsorption of water (hydration) on the β-glucan film. The second process involves the removal of the β-glucan film from the sensor surface. Furthermore, it is suggested that sophorolipids interfere with the hydration of the β-glucan film and suppress increases in its viscosity. This is expected to be an essential factor for the removal of the β-glucan film. Sophorolipids, therefore, show potential for use in cosmetics as an eco-friendly agent for biofilm removal.

Near Chromosome-Level Genome Assembly and Annotation of Rhodotorula babjevae Strains Reveals High Intraspecific Divergence

The genus Rhodotorula includes basidiomycetous oleaginous yeast species. Rhodotorula babjevae can produce compounds of biotechnological interest such as lipids, carotenoids, and biosurfactants from low value substrates such as lignocellulose hydrolysate. High-quality genome assemblies are needed to develop genetic tools and to understand fungal evolution and genetics. Here, we combined short- and long-read sequencing to resolve the genomes of two R. babjevae strains, CBS 7808 (type strain) and DBVPG 8058, at chromosomal level. Both genomes are 21 Mbp in size and have a GC content of 68.2%. Allele frequency analysis indicates that both strains are tetraploid. The genomes consist of a maximum of 21 chromosomes with a size of 0.4 to 2.4 Mbp. In both assemblies, the mitochondrial genome was recovered in a single contig, that shared 97% pairwise identity. Pairwise identity between most chromosomes ranges from 82 to 87%. We also found indications for strain-specific extrachromosomal endogenous DNA. A total of 7591 and 7481 protein-coding genes were annotated in CBS 7808 and DBVPG 8058, respectively. CBS 7808 accumulated a higher number of tandem duplications than DBVPG 8058. We identified large translocation events between putative chromosomes. Genome divergence values between the two strains indicate that they may belong to different species.

Sophorolipid: A glycolipid biosurfactant as a potential therapeutic agent against COVID-19

Biosurfactants are natural surfactants produced by a variety of microorganisms. In recent years, biosurfactants have garnered a lot of interest due to their biomedical and pharmaceutical applications. Sophorolipids are glycolipids types of biosurfactants produced by selected non-pathogenic yeasts. In addition to the detergent activity (reduction in surface and interfacial tension), which is commonly utilized by biomedical applications, sophorolipids have shown some unique properties such as, antiviral activity against enveloped viruses, immunomodulation, and anticancer activity. Considering their antiviral activity, the potential of sophorolipids as an antiviral therapy for the treatment of COVID-19 is discussed in this review. Being a surfactant molecule, sophorolipid could solubilize the lipid envelope of SARS-CoV-2 and inactivate it. As an immunomodulator, sophorolipid could attenuate the cytokine storm caused by the SARS-CoV-2 upon infection, and inhibit the progression of COVID-19 in patients. Sophorolipids could also be used as an effective treatment strategy for COVID-19 patients suffering from cancer. However, there is limited research on the use of sophorolipid as a therapeutic agent for the treatment of cancer and viral diseases, and to modulate the immune response. Nevertheless, the multitasking capabilities of sophorolipids make them potential therapeutic candidates for the bench-to-bedside research for the treatment of COVID-19.

Production of Sophorolipid Biosurfactant by Insect Derived Novel Yeast Metschnikowia churdharensis f.a., sp. nov., and Its Antifungal Activity Against Plant and Human Pathogens

Biosurfactants are potential biomolecules that have extensive utilization in cosmetics, medicines, bioremediation and processed foods. Yeast produced biosurfactants offer thermal resistance, antioxidant activity, and no risk of pathogenicity, illustrating their promising use in food formulations. The present study is aimed to assess potential of biosurfactant screened from a novel yeast and their inhibition against food spoilage fungi. A novel asexual ascomycetes yeast strain CIG-6A^T producing biosurfactant, was isolated from the gut of stingless bee from Churdhar, HP, India. The phylogenetic analysis revealed that the strain CIG-6A^T was closely related to Metschnikowia koreensis, showing 94.38% sequence similarity in the D1D2 region for which the name Metschnikowia churdharensis f.a., sp. nov., is proposed. The strain CIG-6A^T was able to produce sophorolipid biosurfactant under optimum conditions. Sophorolipid biosurfactant from strain CIG-6A^T effectively reduced the surface tension from 72.8 to 35 mN/m. Sophorolipid biosurfactant was characterized using TLC, FTIR, GC-MS and LC-MS techniques and was a mixture of both acidic and lactonic forms. Sophorolipid assessed promising activity against pathogenic fungi viz. Fusarium oxysporum (MTCC 9913), Fusarium solani (MTCC 350), and Colletotrichum gloeosporioides (MTCC 2190). The inhibitory effect of biosurfactant CIG-6A^T against F. solani was studied and MIC was 49 μgm/ml, further confirmed through confocal laser scanning microscopy. We illustrated the antifungal activity of sophorolipid biosurfactant from Metschnikowia genus for the first time and suggested a novel antifungal compound against food spoilage and human fungal pathogen.

Contributions of Glycolipid Biosurfactants and Glycolipid-Modified Materials to Antimicrobial Strategy: A Review

Glycolipid biosurfactants are natural amphiphiles and have gained particular interest recently in their biodegradability, diversity, and bioactivity. Microbial infection has caused severe morbidity and mortality and threatened public health security worldwide. Glycolipids have played an important role in combating many diseases as therapeutic agents depending on the self-assembly property, the anticancer and anti-inflammatory properties, and the antimicrobial properties, including antibacterial, antifungal, and antiviral effects. Besides, their role has been highlighted as scavengers in impeding the biofilm formation and rupturing mature biofilm, indicating their utility as suitable anti-adhesive coating agents for medical insertional materials leading to a reduction in vast hospital infections. Notably, glycolipids have been widely applied to the synthesis of novel antimicrobial materials due to their excellent amphipathicity, such as nanoparticles and liposomes. Accordingly, this review will provide various antimicrobial applications of glycolipids as functional ingredients in medical therapy.

Evaluation of In Vivo toxicity of Novel Biosurfactant from Candida parapsilosis loaded in PLA-PEG Polymeric Nanoparticles

The aim of this study was to evaluate the toxicological profile of biosurfactant encapsulated polymeric nanoparticles of Polylactic acid-Polyethylene glycol (PLA-PEG) in mice. Hematological, biochemical and histopathological samples of rodents were evaluated. Mice were selected randomly and divided into 3 treatment groups and one control group. Group I mice served as a control group, Group II were administrated with biosurfactant, Group III were treated with Polymeric nanoparticles of PLA-PEG. Group IV mice were injected with biosurfactant loaded polymeric nanoparticles of PLA-PEG. The formulations were administered intravenously via tail vein with 20 μg/mL dose concentration of biosurfactant. The normal control group was injected with only PBS. Blood samples were collected on 7th, 14th and 21st day and hematological and biochemical assays were performed. After the blood collection, mice were sacrificed for histopathological examination. The results showed that there were no significant difference in hematology parameter between the control and treated group. Some minute, non-significant changes were found in biochemical parameters which were not considered. Histopathological result of selected vital organs revealed that the biosurfactant and/or PLA-PEG polymeric nanoparticles can be considered as safe as no toxicological features were observed in histopathology of tissues. Hence, it can be deliberated that the biosurfactant encapsulated in PLA-PEG copolymeric nanoparticles are non toxic and can provide a safe, suitable platform for biomedical applications in future.

A review of recent research on antifungal agents against dermatophyte biofilms

Dermatophytoses are inflammatory cutaneous mycoses caused by dermatophyte fungi of the genera Trichophyton, Microsporum, and Epidermophyton that affect both immunocompetent and immunocompromised individuals. With therapeutic failure, dermatophytoses can become chronic and recurrent. This is partly due to their ability to develop biofilms, microbial communities involved in a polymeric matrix attached to biotic or abiotic surfaces, contributing to fungal resistance. This review presents evidence accumulated in recent years on antidermatophyte biofilm activity. The following databases were used: Web of Science, Medline/PubMed (via the National Library of Medicine), Embase, and Scopus. Original articles published between 2011 and 2020, emphasizing the antifungal activity of conventional and new drugs against dermatophyte biofilms were eligible. A total of 11 articles met the inclusion criteria and were reviewed - the studies used in vitro and ex vivo (fragments of nails and hair) experimental models. The articles focused on reports of antibiofilm activity for conventional antifungals, natural drugs, and new therapeutic tools. The strains reported on were T. mentagrophytes, T. rubrum, T. tonsurans, M. canis, and M. gypseum. Between the studies, the wide variability of experimental conditions in vitro and ex vivo was observed. The data suggest the need for methodological standardization (at some minimum). This review systematically presents current studies involving agents that present antibiofilm activity against dermatophytes; and an overview of the ideal in vitro and ex vivo experimental conditions to guarantee biofilm formation that may assist future research.

LAY ABSTRACT

This review presents the current studies on the antibiofilm activities of drugs against dermatophytes and ideal experimental conditions, which might guarantee in vitro and ex vivo biofilm formation. It can be useful to examine the efficacy of new antimicrobial drugs against dermatophytes.

Biosurfactants: The green generation of speciality chemicals and potential production using Solid-State fermentation (SSF) technology

Surfactants are multipurpose products found in most sectors of contemporary industry. Their large-scale manufacturing has been mainly carried out using traditional chemical processes. Some of the chemical species involved in their production are considered hazardous and some industrial processes employing them categorised as "having potential negative impact on the environment". Biological surfactants have therefore been generally accepted worldwide as suitable sustainable greener alternatives. Biosurfactants exhibit the same functionalities of synthetic analogues while having the ability to synergize with other molecules improving performances; this strengthens the possibility of reaching different markets via innovative formulations. Recently, their use was suggested to help combat Covid-19. In this review, an analysis of recent bibliography is presented with descriptions, statistics, classifications, applications, advantages, and challenges; evincing the reasons why biosurfactants can be considered as the chemical specialities of the future. Finally, the uses of the solid-state fermentation as a production technology for biosurfactants is presented.

Microbial Biosurfactants in Cosmetic and Personal Skincare Pharmaceutical Formulations

Cosmetic and personal care products are globally used and often applied directly on the human skin. According to a recent survey in Europe, the market value of cosmetic and personal care products in Western Europe reached about 84 billion euros in 2018 and are predicted to increase by approximately 6% by the end of 2020. With these significant sums of money spent annually on cosmetic and personal care products, along with chemical surfactants being the main ingredient in a number of their formulations, of which many have been reported to have the potential to cause detrimental effects such as allergic reactions and skin irritations to the human skin; hence, the need for the replacement of chemical surfactants with other compounds that would have less or no negative effects on skin health. Biosurfactants (surfactants of biological origin) have exhibited great potential such as lower toxicity, skin compatibility, protection and surface moisturizing effects which are key components for an effective skincare routine. This review discusses the antimicrobial, skin surface moisturizing and low toxicity properties of glycolipid and lipopeptide biosurfactants which could make them suitable substitutes for chemical surfactants in current cosmetic and personal skincare pharmaceutical formulations. Finally, we discuss some challenges and possible solutions for biosurfactant applications.