10.22376/ijpbs.2019.10.1.p1-12 Volume 3 Issue 2 2012 (April - June) In the present work, bio-conversion studies were performed on gallic acid, an important precursor for pharmaceutical industries engaged in manufacture of trimethoprim. Microbiological hydrolysis of two gallotanin rich substrates Chebulic myrobalan and Emblic myrobalan was studied by two fungal strains lessThan i greaterThan Aspergillus niger lessThan /i greaterThan MTCC 281 and lessThan i greaterThan Rhizopus oryzae lessThan /i greaterThan MTCC 1987. Comparative studies were performed using shake flask technique in different variations; high yield of gallic acid was produced by lessThan i greaterThan Aspergillus niger lessThan /i greaterThan from Chebulic myrobalan. G.Umakumar, Mir Naiman Ali, K. Samuel John And Hajera Tabassum Gallic acid, trimethoprim, myrobalan, bio-conversion, Aspergillus niger, Rhizopus oryzae 146-155