Objective: To study the production of pigments by Kocuria sp. BRI 36, their characteristics and influence of heavy metals on pigments.
Methods:The effects of various physical and chemical parameters on pigments production by Kocuria sp. BRI 36 were examined. Pigments were extracted and partially characterised by Thin Layer Chromatography (TLC) and Fourier Transform Infrared Spectroscopy (FTIR). The effects of heavy metals such as Pb 2+ , Cd 2+ , Ni 2+ and Cr 3+ were studied on pigment production. Antimicrobial activity and stability studies of crude pigment were also conducted.Results: Kocuria sp. BRI 36 isolated from cold oceanic region maximally produced red-orange pigment in presence of glucose (5% w/v) and protease peptone (0.2% w/v) at pH 7.5, 10±1 °C. Thin layer chromatography (TLC) analysis revealed the occurrence of three different compounds in the crude pigment belonging to carotenoid and xanthophyll group. Metals like Ni 2+ and Cr 3+ adversely affected pigment production while Pb 2+ and Cd 2+ enhanced the yield. The significant features of Kocuria sp. BRI 36 pigment are i) antimicrobial activity against Gram-positive and Gram-negative bacteria, ii) maximum stability at pH 7.5 and 10±1 °C and iii) ~38% color loss at 50±1 °C in 5 h.
Conclusion:Our results suggest application potential of Kocuria sp. BRI 36 pigments in various biotechnological fields.
Objective: Evaluation of Extracellular Polymeric Substance (EPS) induced heavy metal tolerance in Kocuria sp. BRI 36.Methods: Initially, the effect of different concentrations of glucose (1-10 %) on EPS production by BRI 36 was examined. At optimum glucose concentrations, EPS levels were measured by varying heavy metal concentrations (10-50 ppm) of Pb 2+ , Cd 2+ and Cr 3+Results: Kocuriasp. BRI 36 produced maximum EPS (1g/l) at 5% glucose. Increase in EPS production up to 89% (considering 1g/l as 100%) with an increase in concentrations of heavy metals up to 40 ppm. MTC levels of BRI 36 for heavy metals increased up to 700 ppm when it was cultivated in presence of 5% glucose indicating a major role of surface polymer in metal adsorption. The function of EPS as a protective cover was also evident from an increase in survival percentage of BRI 36 up to 39.4 at MTC. Comparative analysis of extracted crude EPS by FTIR revealed the involvement of O-H, C=O, and C-O-C groups in metal adsorption . Maximum tolerable concentration (MTC) and survival percentage of BRI 36 were determined under conditions that support EPS synthesis. Comparative analysis of extracted crude EPS was performed by Fourier Transform Infrared Spectroscopy (FTIR) to establish functional groups involved in the metal interaction.
Conclusion:Antarctic oceanic isolate Kocuria sp. BRI 36 has an ability to produced EPS under stress conditions of heavy metals. Simultaneously, its MTC values increased due to increase in EPS levels. These observations suggest the possibility to develop gentle, environmentally safe and costeffective method for heavy metal removal.
In Ayurveda, ‘Vidanga’ is one such species high in demand for its various uses. All the species of genus Embelia and Maesa belonging to the family Myrsinaceae are reported as ‘Vidanga’. Considering the availability of plant material in the market there is an ambiguity in supplying the authentic species as ‘Vidanga’. In the present study, a comparative analysis was carried out to determine the efficacy of different 'Vidanga’ spp. in terms of their phyto-constituents, antioxidant potential, and free radical scavenging activity. The highest total phenolic contents (TPCs) and total flavonoid contents (TFCs) were found to be in ethanolic and ethyl acetate extract. Quantitative measurements also showed that abundance of phenolic and flavonoid phytoconstituents was significantly (P<0.001) greater in ethanolic extract of all the ‘Vidanga’ fractions (1.773±0.01 to 137.17±0.19 mg/g GAE and 4.84±0.001 to 302.29±0.07 mg/g of quercetin respectively) than in ethyl acetate extract (1.15±0.003 to 15.12±0.01 mg/g GAE and 7.94±0.05 to 25.20±0.001 mg/g of quercetin respectively). Ethanolic extract of Embelia ribes had significant activity in terms of IC50 than ethyl acetate extracts in the case of 2,2-diphenyl,1- picryl hydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and anti-lipid peroxidation (ALP) (9.53, 9.73 and 6.21 µg/mL respectively) indicates Embelia ribes found to be most effective species as ‘Vidanga’. Pearson’s correlation (r2) analysis also suggests a significant correlation between different antioxidant parameters and bioactive constituents. This study may helpful to draw attention of researchers to characterize the various bioactive compounds from the Embelia ribes in terms of their antioxidant prospective.
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