Fermentative hydrogen production using air purged anaerobic digester sludge and molecular microbiological analysis

Abstract

Hydrogen is widely recognized as a clean and efficient resource for the future. However, approximately 95% of commercially produced hydrogen comes from carbon-containing raw materials, primarily fossil in origin. Given these perspectives, biological hydrogen production assumes paramount importance as an alternative energy resource. Despite its relatively lower yields of hydrogen compared with bio-photolysis processes, fermentative hydrogen production, or dark fermentation, is a promising method of bio-hydrogenation due to its higher rate of hydrogen evolution in the absence of any light source as well as the versatility of the substrates used. Fermentative bio-conversion of biomass resources into hydrogen gas is a charming technology in the aspects of production of clean energy as well as the transformation of waste into environmentally sound materials. Most approaches in environmental engineering have preferred mixed culture as seed material and have been used harsh pretreatment method to harvest hydrogen producing bacteria. However, the suggested methods were expensive and hard to apply in practice so that an economical alternative is necessary. The role and identification of main microorganisms and/or inhibitory microorganisms in a certain system have been paid more attention to by the researchers to understand biological process. In addition, the role and function of fermentative hydrogen producing bacteria and relationship between other microorganisms were not investigated thoroughly until this time. In this study, air purging method was evaluated as an alternative method of well-known pretreatment for fermentative hydrogen production. Moreover, the microbiological observation was kept using molecular microbiological analysis techniques such as terminal restriction fragment lengthy polymorphisms (T-RFLP), denaturing gradient gel electrophoresis (DGGE), and clone library. In the first approach, the basic factors such as initial pH, VSS co...