Fungal and Bacterial Diversity Isolated from Aquilaria malaccensis Tree and Soil, Induces Agarospirol Formation within 3 Months after Artificial Infection

Aquilaria malaccensis Lam, commonly known as Agarwood, is a highly valuable species used in production of agar oil from its infected wood, which is utilized in pharmaceutical and perfumery industry. Agar oil formation in agarwood takes years through the natural process which is induced by natural or artificial injury or microbial infection. The role of soil fungi and bacteria in artificial induction is still an unexplored area. In the present study, we isolated the fungal and bacterial community residing inside the stem of A. malaccensis tree and circumventing soil, samples collected from 21 different sites of the north-eastern state Assam of India and explored their potential in induction of Agarospirol (2-(6,10-Dimethylspiro[4,5]dec-6-en-2-yl)-2-propanol) production by artificially infecting the trees with these microorganisms. A total 340 fungi and 131 bacteria were isolated from 50 stem samples, and 188 fungi and 148 bacteria were isolated from 50 soil samples. Highest Shannon (H′ = 2.43) and Fisher (α = 5.57) diversity index was observed in the stem isolates. The dominant fungal genus was Trichoderma in stem with Pi value of 0.18; while in soil, Aspergillus showed dominance with Pi value 0.73. In bacteria, Bacillus genera showed dominance in both stem and soil samples with Pi = 0.62 and 0.51, respectively. Forty fungal and bacterial isolates were used to assess their potential to induce formation of agarwood in A. malaccensis by artificial infection method. Gas chromatography mass spectroscopy (GC-MS) analysis confirmed development of Agarwood by the presence of Agarospirol compound in samples collected after 3 months of the artificial infection. Only 31% of bacterial and 23% of fungal isolates showed their ability in production of Agarospirol by artificial infection method. Bacteria Pantoea dispersa and fungi Penicillium polonicum showed the highest production in comparison to other isolates

Fungal Endophytes: A Potential Source of Antibacterial Compounds

Antibiotic resistance is becoming a burning issue due to the frequent use of antibiotics for curing common bacterial infections, indicating that we are running out of effective antibiotics. This has been more obvious during recent corona pandemics. Similarly, enhancement of antimicrobial resistance (AMR) is strengthening the pathogenicity and virulence of infectious microbes. Endophytes have shown expression of various new many bioactive compounds with significant biological activities. Specifically, in endophytic fungi, bioactive metabolites with unique skeletons have been identified which could be helpful in the prevention of increasing antimicrobial resistance. The major classes of metabolites reported include anthraquinone, sesquiterpenoid, chromone, xanthone, phenols, quinones, quinolone, piperazine, coumarins and cyclic peptides. In the present review, we reported 451 bioactive metabolites isolated from various groups of endophytic fungi from January 2015 to April 2021 along with their antibacterial profiling, chemical structures and mode of action. In addition, we also discussed various methods including epigenetic modifications, co-culture, and OSMAC to induce silent gene clusters for the production of noble bioactive compounds in endophytic fungi

Optimization and molecular characterization of syngas fermenting anaerobic mixed microbial consortium TERI SA1

The present study focused on the optimization and molecular characterization of anaerobic mixed consortium TERI SA1 that can utilize synthesis gas as sole carbon source for volatile fatty acids production. Optimization study using Box- Behnken design and RSM methodology was carried out in order to investigate the effect of three medium factors on metabolite formation from synthesis gas bioconversion: (yeast extract (0.0–2.0 g/L), ammonium chloride (0.0–1.5 g/L) and corn steep liquor (0.0-10 g/L). Optimized parameters enhanced the production of volatile fatty acids upto 3.9 g/L, which indicated an increase of around 289 % from the non-optimized conditions. Furthermore, two approaches were used for isolation and phylogenetic identification of anaerobic consortium TERI SA1 involving 16S rRNA sequencing of culturable bacterial isolates as well as meta-genomic approach (by making a 16S rRNA gene library of total community DNA). Based on similarity search with NCBI database selected positive clones were most closely related with acetogenic microorganisms Clostridium scatalogenes, Clostridium carboxydivorans, Clostridium drakei and Uncultured Clostridium sp. and strains isolated by culturable method (ASH051 and ASH 052) with Clostridium scatalogenes, and Clostridium drakei. These strains have previously been reported for acetic acid production from syngas bioconversion. Article History: Received July 16th 2017; Received in revised form September 13rd 2017; Accepted Sept 28th 2017; Available online How to Cite This Article: Singla, A., Kumar, S., Lavania, M., Chhipa, H., Kapardar, R., Rastogi, S., Lal, B., and Sarma, P.M. (2017) Optimization and Molecular Characterization of Syngas Fermenting Anaerobic Mixed Microbial Consortium TERI SA1.International Journal of Renewable Energy Development, 6(3), 241-251. https://doi.org/10.14710/ijred.6.3.241-25

Chemical Composition of an Aphid Antifeedant Extract from an Endophytic Fungus, Trichoderma sp. EFI671

Botanical and fungal biopesticides, including endophytes, are in high demand given the current restrictive legislations on the use of chemical pesticides. As part of an ongoing search for new biopesticides, a series of fungal endophytes have been isolated from selected medicinal plants including Lauraceae species. In the current study, an extract from the endophytic fungus Trichoderma sp. EFI 671, isolated from the stem parts of the medicinal plant Laurus sp., was screened for bioactivity against plant pathogens (Fusarium graminearum, Rhizoctonia solani, Sclerotinia sclerotiorum and Botrytis cinerea), insect pests (Spodoptera littoralis, Myzus persicae, Rhopalosiphum padi) and plant parasites (Meloidogyne javanica), with positive results against M. persicae. The chemical study of the neutral fraction of the active hexane extract resulted in the isolation of a triglyceride mixture (m1), eburicol (2), β-sitostenone (3), ergosterol (4) and ergosterol peroxide (5). The free fatty acids present in the acid fraction of the extract and in m1 (oleic, linoleic, palmitic and stearic) showed strong dose-dependent antifeedant effects against M. persicae. Liquid (potato dextrose broth, PDB and Sabouraud Broth, SDB) and solid (corn, sorghum, pearl millet and rice) growth media were tested in order to optimize the yield and bioactivity of the fungal extracts. Pearl millet and corn gave the highest extract yields. All the extracts from these solid media had strong effects against M. persicae, with sorghum being the most active. Corn media increased the methyl linoleate content of the extract, pearl millet media increased the oleic acid and sorghum media increased the oleic and linoleic acids compared to rice. The antifeedant effects of these extracts correlated with their content in methyl linoleate and linoleic acid. The phytotoxic effects of these extracts against ryegrass, Lolium perenne, and lettuce, Lactuca sativa, varied with culture media, with sorghum being non- toxic.This work has been supported by grants from Department of Science and Technology (Grant noDST/INT/SPAIN/P-3/-9); Department of Biotechnology (Grant No. BT/PR9324/NDB/39/334/2013); ACI2009-0900(MCIN), I-Coop Agrofood-2014 CD0015 (CSIC), CTQ2015-64049-C3-1-R (MINECO/FEDER); and JAE-CSIC(predoctoral fellowship to L.F. Julio).Peer reviewe