The applicability of ultrasonication for enhancement of hydrogen production from food wastes was evaluated in three different systems. System A is a conventional continuously-stirred tank reactor (CSTR) fed raw food waste; system B is a conventional continuously-stirred tank reactor fed sonicated food waste, and system C (US patent-pending) is the sonicated biological hydrogen reactor (SBHR) which comprised a CSTR connected with an ultrasonic probe at the bottom of the reactor. In this study, the increase in hydrogen production rate relative to the control (system A) due to sonication of the feed before the digestion was 27%, compared to 90% in the SBHR. Similarly, the CSTR with sonicated feed exhibited a 23% increase in hydrogen yield as mol H(2)/mol hexose(consumed) compared to a 62% increase in the SBHR relative to the control (system A). The VSS destruction in the SBHR was higher than those in the CSTR and CSTR with sonicated feed by 50% and 60%, respectively. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.