Beet molasses and black strap are two major waste streams of the sugar industry. They both contain high amounts of sucrose, making them suitable substrates for biological hydrogen production. Photofermentation, usually used to convert organic acids to hydrogen, has the potential capacity to effectively use a variety of feed stocks, including sugars. A comparative study on photofermentative biohydrogen production from beet molasses, black strap, and sucrose was conducted. With yields of 10.5 mol H-2/mol sucrose for beet molasses (1 g/l sugar); 8 mol H-2/mol sucrose for black strap (1 g/l sugar) and 14 mol H-2/mol sucrose for pure sucrose, a one stage photofermentation system appears promising as an alternative to two-stage systems given the potential savings in energy input and operational costs. (C) 2012 Elsevier Ltd. All rights reserved.