Abirami Baskaran

Microbial biotransformation of para-hydroxycinnamic acids (pHCAs) such as para-coumaric, caffeic, ferulic and sinapic acids into vinylphenols is catalyzed by phenolic acid decarboxylases (PADs), while reduction to their corresponding aldehydes and alcohols is mediated by carboxylic acid reductases (CARs) and alcohol dehydrogenases (ADHs), respectively. The present study systematically evaluated a diverse set of endophytic and basidiomycetes fungi as whole-cell biocatalysts for the transformation of pHCAs into their corresponding vinylphenols and/or aldehydes and alcohols. Twenty-three fungal strains were screened for their PAD, CAR and ADH activities. Based on ultra-high-performance liquid chromatography–diode array detector (UHPLC-DAD) analysis, fourteen strains were selected for preparative-scale biotransformations across all four substrates. Previous literature largely emphasizes enzyme activity or single substrates, seldom covering all four pHCAs. The strain Umbelopsis sp. JAR-T demonstrated promising biotransformation of para-coumaric acid and ferulic acid to 4-vinylphenol (28% isolated yield) and 4-vinylguaiacol (40% isolated yield), respectively, with minimal by-product formation. The results highlight endophytic fungi as largely untapped and versatile biocatalysts for pHCA biotransformation and establish whole-cell fungal systems as robust, non-recombinant alternatives to engineered platforms. This integrated screening-to-preparative workflow provides a scalable framework for the production of value-added compounds with potential applications in the food, cosmetic and pharmaceutical industries.

The growing emergence of multi-drug resistant microbial strains has kept the scientific world searching for novel bioactive compounds with specific chemical characteristics. Accordingly, researchers have started exploring the understudied metabolites from endophytes as a new source of bioactive compounds. In this context, the current study was designed to evaluate the bioactive properties of endophytic fungi from the Mokrzański forest in Wrocław, Poland that have not yet been fully researched. Forty-three endophytic fungi were isolated from twelve distinct plants. Following their cultivation, fungal extracts were separately prepared from biomass and cell-free filtrates, and their antibacterial, antifungal (against human and plant pathogens), and antioxidant properties were examined. Five promising fungi after screening were identified to possess all of these activities. These strains and their respective plant hosts were Trichoderma harzianum BUK-T (Fagus sylvatica), Aspergillus ochraceus ROB-L1 (Robinia pseudoacacia), Chaetomium cochliodes KLON-L1, Fusarium tricinctum KLON-L2 (Acer platanoides), and Penicillium chrysogenum SOS-B2 (Pinus sylvestris). Moreover, gamma irradiation at several doses (Gy) was separately applied to the fungal cultures to study their effects on the recorded activities. Finally, compounds after preparative thin-layer chromatography fractionation of the five fungal strains were identified by GC-MS. These findings suggest that the isolated endophytic fungi could serve as novel sources of bioactive metabolites with antibacterial, antifungal, and antioxidant properties, potentially paving the way for future research and the development of new bioactive compounds.

The aim of this investigation is to produce and characterize biosurfactant from Streptomyces sp. HRB1 and to evaluate its biomedical and bioremediation potential. Biosurfactant producing property of Streptomyces sp. HRB1 isolated from petroleum contaminated soil was confirmed by hemolytic and oil spread assays. Based on the results of FT‐IR spectral and GC–MS analysis, the biosurfactant was confirmed as glycolipid type. Biosurfactant from Streptomyces sp. HRB1 exhibited 71% inhibition against Pseudomonas aeruginosa biofilm formation, 77.33% quorum sensing inhibition property against Chromobacterium violeceum MTCC 2656, more than 80% inhibition in antioxidant assays namely, DPPH, ABTS, and metal chelation, promising anti‐proliferative activity against leukemia and myeloma cells with low IC₅₀ values, 96% decolorization of malachite green within 48 h of reaction time, and minimal toxicity against normal cell lines in dose‐dependent manner. The taxonomic position of the potential strain HRB1 was further confirmed as Streptomyces enissocaesilis HRB1 based on their phenotypic and molecular characteristics. To conclude, Streptomyces enissocaesilis HRB1 isolated from petroleum‐contaminated soil is a promising source for low‐cost production of glycolipid biosurfactant with potential biomedical and environmental applications such as antiphytofungal, antibiofilm, anti‐quorum sensing, antioxidant, anticancer, and dye degradation properties.

The entire globe is reeling under the magnitude of the current corona virus pandemic. This menace has proposed severe health and economic threats for all, thereby challenging our human existence itself. Since its outbreak, it has raised the concern and imperative need of developing novel and effective agents to combat viral diseases and now its variants as well. Despite the sincere and concerted efforts of scientists and pharma giants all over the world, there seems to be no ideal recourse found till date. Natural products are rich sources of novel compounds used in the treatment of infectious and non-infectious diseases. There are reports on natural products from microbes, plants and marine organisms that are active against viral targets. Actinobacteria, the largest phylum under the bacterial kingdom, is known for its secondary metabolite production with diverse bioactive potentials. Nearly 65% of antibiotics used in medicine are contributed by Actinobacteria. Compared to antibacterial and antifungal agents, antiviral compounds from Actinobacteria are less studied. In recent years Actinobacteria from under studied/extreme ecosystems are explored for their antiviral properties. Ivermectin and teicoplanin are examples of Actinobacteria-derived antiviral drugs available for commercial use. This review highlights the importance of actinobacteria as future sources of antiviral drug discovery.

Marine microbes genetically evolved to survive varying salinity, temperature, pH, and other stress factors by producing different bioactive metabolites. These microbial secondary metabolites (SMs) are novel, have high potential, and could be used as lead molecule. Genome sequencing of microbes revealed that they have the capability to produce numerous novel bioactive metabolites than observed under standard in vitro culture conditions. Microbial genome has specific regions responsible for SM assembly, termed biosynthetic gene clusters (BGCs), possessing all the necessary genes to encode different enzymes required to generate SM. In order to augment the microbial chemo diversity and to activate these gene clusters, various tools and techniques are developed. Metagenomics with functional gene expression studies aids in classifying novel peptides and enzymes and also in understanding the biosynthetic pathways. Genome shuffling is a high-throughput screening approach to improve the development of SMs by incorporating genomic recombination. Transcriptionally silent or lower level BGCs can be triggered by artificially knocking promoter of target BGC. Additionally, bioinformatic tools like antiSMASH, ClustScan, NAPDOS, and ClusterFinder are effective in identifying BGCs of existing class for annotation in genomes. This review summarizes the significance of BGCs and the different approaches for detecting and elucidating BGCs from marine microbes.