title: Inhibitory activity of pine needle tannin extracts on some agriculturally resourceful microbes.
abstract: Crude extracts of water and solvent extractable tannin fractions from pine needles were found to contain tannin concentrations of 10.15% and 13.15% tannic acid equivalents respectively. Thin Layer Chromatography revealed the presence of four distinct phenolic compounds, amongst which two were tannic acid like compounds. Both the extracts were found to be inhibitory to several microbes of agricultural importance. Amongst the bacterial strains studied, Azotobacter sp (VL-A2) was able to tolerate upto 1000 ppm of crude tannin concentration without any growth inhibition. While growth of Rhizobium (VL-R1) and Bacillus halodurans (MTCC 7181) was inhibited by crude tannin concentrations of 50 and 100 ppm respectively of both water and solvent extracted tannins. Among the fungal genera, Pleurotus djamor was found to tolerate up to 10000 ppm of crude tannins, while Trichoderma virescens (MTCC 6321) and T. reesii could tolerate up to 3000 ppm of both water extractable and acetone extractable crude tannins without any growth inhibition.
authors.affiliation: Vivekananda Parvatiya Krishi Anusandhan Sansthan (ICAR), Almora, 263 601 Uttarakhand India.
authors.forename: G
authors.initials: G
authors.lastname: Selvakumar
authors.forename: Supradip
authors.initials: S
authors.lastname: Saha
authors.forename: S
authors.initials: S
authors.lastname: Kundu
keywords: Agriculture; Inhibitory activity; Microbial inoculants; Pine needle; Tannin