Natural inducement of hydrogen from food waste by temperature control

Abstract

An easy and simple method of producing H(2) from food waste was devised. Although there was no inoculum addition or pretreatment, food waste was naturally decomposed and converted to H2 when cultivated at 50-60 degrees C in anaerobic state. Both the highest H(2) yield of 1.79 mol H(2)/mol hexoseadded and a production rate of 369.1 ml H(2)/L/h were observed at 50 degrees C. While butyrate was the main by-product of the food waste cultivated at 50 degrees C, lactate whose producing-reaction is non-hydrogenic was dominant at 35 degrees C where the worst performance was observed. The degradation efficiency of volatile solids and carbohydrate was similar to 50% and 90%, respectively, at both temperatures. Polymerase chain reaction-denaturing gradient gel electrophoresis analysis clearly revealed that the role of temperature control was the microbial selection. At high temperature, the activity of indigenous lactic acid bacteria was suppressed while H(2)-producing bacteria, such as Clostridium sp., Acetanaerobacterium elongatum, and Caloramater indicus, were predominantly cultivated. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.