Based on the generation of Pantoea agglomerans BH18 library using Tn7 transposon system, mutant screens were conducted for improvement the ability of hydrogen production of this strain. These mutants were used to test for ability of hydrogen production in the initial pH of 5.0. In contrast to wild type strain BH18, a transposon mutant, named as strain TB108, was screened for high hydrogen-producing capability and acid tolerance in the initial pH of 5.0. The factors required for hydrogen production of the aciduric transposon-mutagenized strain TB108 were determined. The mutant strain TB108 similar as wild type strain BH18 was able to produce hydrogen over a wide range of salt concentration from 0.4% to 6%. Under the marine conditions with the initial pH of 5.0 and glucose concentration of 10 g/L, the total hydrogen production of the mutant TB108 was (1.36 +/- 0.04) mol H-2/mol glucose (mean +/- SE.), increasing by 55% compared with wild type. In addition, the mutant strain TB108 could produce hydrogen using many carbon sources such as fructose, glucose, sucrose, sorbitol and so on. This result demonstrated that the mutant strain with high acid tolerance is beneficial for improvement of hydrogen production. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.