Biosynthesis of vanillic acid by Ochrobactrum anthropi and its applications.

Vanillic acid has always been in high-demand in pharmaceutical, cosmetic, food, flavor, alcohol and polymer industries. Present study achieved highly pure synthesis of vanillic acid from vanillin using whole cells of Ochrobactrum anthropi strain T5_1. The complete biotransformation of vanillin (2 g/L) in to vanillic acid (2.2 g/L) with 95 % yield was achieved in single step in 7 h, whereas 5 g/L vanillin was converted to vanillic acid in 31 h. The vanillic acid thus produced was validated using LC-MS, GC-MS, FTIR and NMR. Further, vanillic acid was evaluated for in vitro anti-tyrosinase and cytotoxic properties on B16F1 skin cell line in dose dependent manner with IC50 values of 15.84 mM and 9.24 mM respectively. The in silico Swiss target study predicted carbonic acid anhydrase IX and XII as key targets of vanillic acid inside the B16F1 skin cell line and revealed the possible mechanism underlying cell toxicity. Molecular docking indicated a strong linkage between vanillic acid and tyrosinase through four hydrogen and several hydrophobic bonds, with ΔG of -3.36 kJ/mol and Ki of 3.46 mM. The bioavailability of vanillic acid was confirmed by the Swiss ADME study with no violation of Lipinski's five rules.

HPLC, NMR based chemical profiling and biological characterisation of Indian propolis.

The present study aimed to investigate chemical profile, antioxidant and antimicrobial activities of Indian Melifera propolis (IMP) samples collected from 13 different states. Chemical characterisation of ethanolic extracts of IMP (EEMP) samples was carried out by using HPLC and 1HNMR spectroscopy. The antioxidant activity of EEMP samples was measured by DPPH, ABTS, and FRAP assay. Moreover, the antimicrobial activity of each EEMP sample tested against bacteria and yeast using a 96 well plate microdilution method. All EEMP samples had remarkable antioxidant and antimicrobial activities. The antioxidant potential of EEMP samples found to have a moderate positive correlation with their total phenolics and flavonoids content. Majority of EEMP samples had a minimum inhibitory concentration (MIC) ≤1mg/mL against Staphylococcus aureus. Chemometric analysis of 1HNMR data indicated that brown, green, green-brown, red and red-brown coloured IMP samples were chemically distinct from each other, and showed two separate clusters for northern and southern states propolis samples. HPLC analysis confirmed phenethyl caffeate was most common and abundant compound in IMP samples among studied compounds. In conclusion, this study may be helpful for defining the quality of IMP as a raw material, and also in finished food and health care products.

Enhanced Detoxification of Arsenic Under Carbon Starvation: A New Insight into Microbial Arsenic Physiology.

Nutrient availability in nature influenced the microbial ecology and behavior present in existing environment. In this study, we have focused on isolation of arsenic-oxidizing cultures from arsenic devoid environment and studied effect of carbon starvation on rate of arsenite oxidation. In spite of the absence of arsenic, a total of 40 heterotrophic, aerobic, arsenic-transforming bacterial strains representing 18 different genera were identified. Nineteen bacterial species were isolated from tannery effluent and twenty-one from tannery soil. A strong co-relation between the carbon starvation and arsenic oxidation potential of the isolates obtained from the said niche was observed. Interestingly, low carbon content enhanced the arsenic oxidation ability of the strains across different genera in Proteobacteria obtained. This represents the impact of physiological response of carbon metabolism under metal stress conditions. Enhanced arsenic-oxidizing ability of the strains was validated by the presence of aio gene and RT-PCR, where 0.5- to 26-fold up-regulation of arsenite oxidase gene in different genera was observed. The cultures isolated from tannery environment in this study show predominantly arsenic oxidation ability. This detoxification of arsenic in lack of carbon content can aid in effective in situ arsenic bioremediation.

Simultaneous reduction of Cr(VI) and oxidation of As(III) by Bacillus firmus TE7 isolated from tannery effluent.

Hexavalent chromium [Cr(VI)] and arsenite [As(III)] are the most toxic forms of chromium and arsenic respectively, and reduction of Cr(VI) to Cr(III) and oxidation of As(III) to As(V) has great environmental implications as they affect toxicity and mobility of these toxic species. Bacillus firmus strain TE7, resistant to chromium and arsenic was isolated from tannery effluent. The strain exhibited ability to reduce Cr(VI) and oxidize As(III). It reduced 100 mg L(-1) Cr(VI) within 60 h in nutrient broth and oxidized 150 mg L(-1) As(III) within 10 h in minimal medium. It also completely reduced 15 mg L(-1) Cr(VI) and oxidized 50 mg L(-1) of As(III) simultaneously in minimal medium. To the best of our knowledge, this is the first bacterial strain showing simultaneous reduction of Cr(VI) and oxidation of As(III) and is a potential candidate for bioremediation of environments contaminated with these toxic metal species.