Minki Munjal

Bio: Minki Munjal is an academic researcher from VIT University. The author has contributed to research in topics: Agar plate & Tyrosinase. The author has an hindex of 3, co-authored 3 publications receiving 41 citations.

Isolation and characterization of tyrosinase produced by marine actinobacteria and its application in the removal of phenol from aqueous environment

Abstract: The present study was focused on screening and characterization of tyrosinase enzyme produced by marine actinobacteria and its application in phenolic compounds removal from aqueous solution. A total of 20 strains were isolated from marine sediment sample and screened for tyrosinase production by using skimmed milk agar medium. Among 20 isolates, two isolates LK-4 and LK-20 showed zone of hydrolysis and these were taken for secondary screening by using tyrosine agar medium. Based on the result of secondary screening LK-4 was selected for further analysis, such as tyrosinase assay, protein content and specific activity of the enzyme. The tyrosinase enzyme was produced in a SS medium and was partially purified by ammonium sulfate precipitation, dialysis and SDS PAGE. The isolate (LK-4) was identified as Streptomyces espinosus using 16S rRNA gene sequencing and named as “Streptomyces espinosus strain LK4 (KF806735)”. The tyrosinase enzyme was immobilized in sodium alginate which was applied to remove phenolic compounds from water. The enzyme efficiently removed the phenolic compounds from aqueous solution within few hours which indicated that tyrosinase enzyme produced by Streptomyces espinosus strain LK-4 can be potently used for the removal of phenol and phenolic compounds from wastewater in industries.

Phytochemical Composition, Antioxidant, Antimicrobial and Cytotoxic Potential of Methanolic Extracts of Adhatoda vasica (Acanthaceae)

Abstract: The aim of this study was to evaluate Adhatoda vasica leaves for its phytochemical composition and antioxidant activity. Antioxidant activity of methanol extract of A. vasica was estimated by total antioxidant activity, 2,2 diphenyl1-picrylhydrazyl radical scavenging activity, reducing power potential and iron chelating activity. Antimicrobial activity was performed by agar well diffusion method. Estimation of total phenolic content was measured by Folin-Ciocalteu reagent method and estimation of total flavonoid content was performed by aluminum chloride method. Leaves of A. vasica were found to possess saponins, oils and fats, phytosterol, phenolic compounds, tannins, carbohydrate, alkaloids, flavanoids and proteins. Extract showed high antioxidant activity in various antioxidant experiments. The extract of A. vasica showed presence of high levels of polyphenolic compounds (phenolic compounds and flavonoids), which could be the possible reason behind the antioxidant activity of the plant. In addition extract demonstrated moderat antimicrobial and cytotoxic activity (brine shrimp lethality).

Isolation and characterization of pigment producing marine actinobacteriafrom mangrove soil and applications of bio-pigments

Abstract: The present study is focused on the extraction of intracellular pigment from actinobacteria isolated from the wetland soil sample of Sundarbans, West Bengal. Out of a total 20 isolates, only one actinobacterial isolates showed pigmented growth. Further, the potential isolate was identified by using 16s rRNA sequencing and confirmed as Streptomyces fradiae VITIPMSB. The intracellular pigment was extracted by cell disruption technique using ethyl acetate as the solvent. Partial characterizations of the pigment were carried out using UV-Visible spectrophotometry and FT-IR spectroscopy. The extracted pigment was applied for the preparation of lip balm and assessing its textile dyeing property. In addition, extracted pigment was analyzed for antioxidant and hemolytic activity. The obtained results showed potent antioxidant activity and confers the bio-pigmentas non-toxic to human erythrocytes

Recent developments in the use of tyrosinase and laccase in environmental applications

Abstract: Our current global environmental challenges include the reduction of harmful chemicals and their derivatives. Bioremediation has been a key strategy to control the massive presence of chemicals in the environment. Enzymes including the phenoloxidases, laccases and tyrosinases, are increasingly being investigated as “green products” in the removal of many chemical contaminants in waters and soils. Both phenoloxidases are widespread in nature and attractive biocatalysts due to their ability to use readily available molecular oxygen as sole cofactor for their catalytic elimination of a large number of chemicals. Taking advantage of their catalytic potentials, remarkable advances have been made in the engineering of laccases to produce suitable biocatalysts in environmental applications. Studies about novel strategies of laccase immobilization and insolubilization for the treatment of chemical contaminants were provided. Likewise, tyrosinases are gaining increasing interest in environmental applicatio...

Marine Actinomycetes, New Sources of Biotechnological Products

Abstract: The Actinomycetales order is one of great genetic and functional diversity, including diversity in the production of secondary metabolites which have uses in medical, environmental rehabilitation, and industrial applications. Secondary metabolites produced by actinomycete species are an abundant source of antibiotics, antitumor agents, anthelmintics, and antifungals. These actinomycete-derived medicines are in circulation as current treatments, but actinomycetes are also being explored as potential sources of new compounds to combat multidrug resistance in pathogenic bacteria. Actinomycetes as a potential to solve environmental concerns is another area of recent investigation, particularly their utility in the bioremediation of pesticides, toxic metals, radioactive wastes, and biofouling. Other applications include biofuels, detergents, and food preservatives/additives. Exploring other unique properties of actinomycetes will allow for a deeper understanding of this interesting taxonomic group. Combined with genetic engineering, microbial experimental evolution, and other enhancement techniques, it is reasonable to assume that the use of marine actinomycetes will continue to increase. Novel products will begin to be developed for diverse applied research purposes, including zymology and enology. This paper outlines the current knowledge of actinomycete usage in applied research, focusing on marine isolates and providing direction for future research.

Streptomyces spp. in the biocatalysis toolbox.

Abstract: About 20,100 research publications dated 2000-2017 were recovered searching the PubMed and Web of Science databases for Streptomyces, which are the richest known source of bioactive molecules. However, these bacteria with versatile metabolism are powerful suppliers of biocatalytic tools (enzymes) for advanced biotechnological applications such as green chemical transformations and biopharmaceutical and biofuel production. The recent technological advances, especially in DNA sequencing coupled with computational tools for protein functional and structural prediction, and the improved access to microbial diversity enabled the easier access to enzymes and the ability to engineer them to suit a wider range of biotechnological processes. The major driver behind a dramatic increase in the utilization of biocatalysis is sustainable development and the shift toward bioeconomy that will, in accordance to the UN policy agenda "Bioeconomy to 2030," become a global effort in the near future. Streptomyces spp. already play a significant role among industrial microorganisms. The intention of this minireview is to highlight the presence of Streptomyces in the toolbox of biocatalysis and to give an overview of the most important advances in novel biocatalyst discovery and applications. Judging by the steady increase in a number of recent references (228 for the 2000-2017 period), it is clear that biocatalysts from Streptomyces spp. hold promises in terms of valuable properties and applicative industrial potential.