Enhanced candicidal compound production by a new soil isolate Penicillium verruculosum MKH7 under submerged fermentation.

BACKGROUND: Microorganisms are a rich source of structurally diverse secondary metabolites that exert a major impact on the control of infectious diseases and other medical conditions. The biosynthesis of these metabolites can be improved by manipulating the nutritional or environmental factors. This work evaluates the effects of fermentation parameters on the production of a lactone compound effective against Candida albicans by Penicillium verruculosum MKH7 under submerged fermentation. Design-Expert version8.0 software was used for construction of the experimental design and statistical analysis of the experimental data. RESULTS: The important factors influencing antibiotic production selected in accordance with the Plackett-Burman design were found to be initial pH, temperature, peptone, MgSO4.7H2O. Orthogonal central composite design and response surface methodology were adopted to further investigate the mutual interaction between the variables and identify the optimum values that catalyse maximum metabolite production. The determination coefficient (R2) of the fitted second order model was 0.9852. The validation experiments using optimized conditions of initial pH 7.4, temperature 27 °C, peptone 9.2 g/l and MgSO4.7H2O 0.39 g/l resulted in a significant increase (almost 7 fold from 30 to 205.5 mg/l) in the metabolite production which was in agreement with the prediction (211.24 mg/l). Stability of the compound was also assessed on the basis of its response to physical and chemical stresses. CONCLUSIONS: So far as our knowledge goes, till date there are no reports available on the production of antibiotics by Penicillium verruculosum through media optimization using RSM. Optimization not only led to a 7 fold increase in metabolite yield but the same was achieved at much lesser time (8-10 days compared to the earlier 12-15 days). The enhanced yield of the antibiotic strongly suggests that the fungus P. verruculosum MKH7 can be efficiently used for antibiotic production on a large scale.

Effect of physicochemical parameters on nitrile-hydrolyzing potentials of newly isolated nitrilase of Fusarium oxysporum f. sp. lycopercisi ED-3.

In recent years, nitrilases from fungus have received increasing attention, and most of the studies are performed on nitrilases of bacterial origin. Frequently used methods are based on analytical methods such as high-performance liquid chromatography, liquid chromatography-mass spectrometry, and gas chromatography; therefore, an efficient, user friendly, and rapid method has been developed to screen nitrilase enzyme based on the principle of color change of a pH indicator. Phenol red amended with the minimal medium appears light yellow at neutral pH, which changes into pink with the formation of ammonia, indicating nitrilase activity in the reaction medium. A highly potent strain ED-3 identified as Fusarium oxysporum f. sp. lycopercisi (specific activity 17.5 µmol/Min/mg dcw) was isolated using this method. The nitrilase activity of F. oxysporum f. sp. lycopercisi ED-3 strain showed wide substrate specificity toward aliphatic nitriles, aromatic nitriles, and orthosubstituted heterocyclic nitriles. 4-Aminobenzonitrile was found to be a superior substrate among all the nitriles used in this study. This nitrilase was active within pH 5-10 and temperature ranging from 25 to 60 °C with optimal at pH 7.0 and temperature at 50 °C. The nitrilase activity was enhanced to several folds through optimization of culture and biotransformation conditions from 1,121 to 1,941 µmol/Min.

Bioprospecting Micromonospora from Kaziranga National Park of India and their anti-infective potential.

Large number of strains was isolated from soils of Kaziranga National Park of North-East India using selective isolation procedure. They were assigned to the genus Micromonospora on the basis of their typical colonial and pigmentation features. The taxonomic identities of the isolates were confirmed on the basis of their molecular characters (16SrDNA). A total of one hundred Micromonospora strains were isolated during the present investigation. The diagnostic cell wall sugar and amino acids were determined from these Micromonospora strains. After preliminary screening most of the isolates exhibited excellent anti-infective activity against human bacterial pathogens Staphylococcus aureas, Bacillus subtilis, Proteus vulgaris, Echerichia coli, Pseudomonas aeroginosa and fungal pathogens Aspergillus niger, Fusarium oxysporum and Candida albicans. Among these isolates one strain designated as HK-10 showed promising activity against human pathogens S. aureas, B. subtilis, P. vulgaris and P. aeroginosa.

Simultaneous Identification and Quantification of Three Xanthones and Two Polyisoprenylated Benzophenones in Eight Indian Garcinia Species Using a Validated UHPLC-PDA Method.

Background: Xanthones and polyisoprenylated benzophenones (PIBs) are two important classes of plant secondary metabolites with a wide range of bioactivities. Garcinia species synthesize numerous xanthones and PIBs. As per the literature, no data claiming simultaneous identification and quantification of three xanthones, α-mangostin, ß-mangostin, γ-mangostin, and two PIBs, xanthochymol, isoxanthochymol, were found. Methods: A validated ultra-HPLC (UHPLC)-photodiode array (PDA) method for the simultaneous identification and quantification of five compounds in different extracts of eight Indian Garcinia species was developed. The compounds were separated on a Waters ACQUITY™ UPLC H-Class column using a mobile phase consisting of solvents 0.1% formic acid in water (A) and methanol (B) in gradient elution mode. The total run time was 9 min. Results: From fruit rinds of eight Indian Garcinia species, namely Garcinia cambogia, G. cowa, G. indica, G. loniceroides, G. mangostana, G. morella, G. pedunculata, and G. xanthochymus, extracts were prepared using solvents of varying polarity. These extracts were analyzed for five biologically important compounds, namely α-mangostin, ß-mangostin, γ-mangostin, xanthochymol, and isoxanthochymol. The results revealed that there is a wide variation in concentration of these compounds in extracts of Garcinia species. Conclusions: The developed and validated UHPLC-PDA method could be used for simultaneous identification and quantification of these five compounds for bioprospection of other Garcinia species.

Complete genome sequencing and comparative analyses of broad-spectrum antimicrobial-producing Micromonospora sp. HK10.

Micromonospora genus produces >700 bioactive compounds of medical relevance. In spite of its ability to produce high number of bioactive compounds, no genome sequence is available with comprehensive secondary metabolite gene clusters analysis for anti-microbial producing Micromonospora strains. Thus, here we contribute the full genome sequence of Micromonospora sp. HK10 strain, which has high antibacterial activity against several important human pathogens like, Mycobacterium abscessus, Mycobacterium smegmatis, Bacillus subtillis, Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella and Escherichia coli. We have generated whole genome sequence data of Micromonospora sp. HK10 strain using Illumina NexSeq 500 sequencing platform (2×150bp paired end library) and assembled it de novo. The sequencing of HK10 genome enables identification of various genetic clusters associated with known- and probably unknown- antimicrobial compounds, which can pave the way for new antimicrobial scaffolds.

Draft Genome Sequence of Micromonospora sp. Strain HK10, Isolated from Kaziranga National Park, India.

We report the 6.92-Mbp genome sequence of Micromonospora sp. HK10, isolated from soil samples collected from Kaziranga National Park, Assam, India. The full genome of strain Micromonospora sp. strain HK10 consists of 6,911,179 bp with 73.39% GC content, 6,196 protein-coding genes, and 86 RNAs.

Enantioconvergent biohydrolysis of racemic styrene oxide to R-phenyl-1, 2-ethanediol by a newly isolated filamentous fungus Aspergillus tubingensis TF1.

An effort was made to isolate biocatalysts hydrolyzing epoxides from various ecological niches of northeast India, a biodiversity hot spot zone of the world and screened for epoxide hydrolase activity to convert different racemic epoxides to the corresponding 1, 2-vicinal diols. Screening of a total of 450 microorganisms isolated was carried out using NBP colorimetric assay. One of the strains TF1, after internal transcribed spacer sequence analysis, identified as Aspergillus tubingensis, showed promising enantioconvergent epoxide hydrolase activity. The hydrolysis of unsubstituted styrene oxide (1) occurred to give 97 % ee of R-(-)-1-phenylethane-1, 2-diol (6) with more than 99 % conversion within 45 min incubation. It is shown to be a cheap and practical biocatalyst for one step asymmetric synthesis of chiral R-diol. The other representative substrates (2-5), although underwent hydrolysis with more than 99 % conversion beyond 15 h, exhibited poor enantioselectivity.