A mesophilic alkaline tolerant fermentative microbe was isolated from estuarine sediment samples and designated as Clostridium butyricum TM-9A, based on 16S rRNA gene sequence. Batch experiments were conducted for investigation of TM-9A strain for its growth and hydrogen productivity from glucose, in an iron containing basal solution supplemented with yeast extract as organic nitrogen source. Hydrogen production started to evolve when cell growth entered exponential phase and reached maximum production rate at late exponential phase. Maximum hydrogen production was observed at 37 degrees C, initial pH of 8.0 in the presence of 1% glucose. Optimization of process parameters resulted in increase in hydrogen yield from 1.64 to 2.67 mol of H-2/mol glucose. Molar yield of H-2 increased further from 2.67 to 3.1 mol of H-2/mol of glucose with the decrease in hydrogen partial pressure, obtained by lowering the total pressure in the head space of the batch reactor. Acetate and butyrate were the measure volatile fatty acids generated during hydrogen fermentation. TM-9A strain produced hydrogen efficiently from a range of pentose and hexose sugars including di-, tri and poly-saccharides like; xylose, ribose, glucose, rhamnose, galactose, fructose, mannose, sucrose, arabinose, raffinose, cellulose, cellobiose and starch. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.