The effect of support particle type on thermophilic hydrogen production by immobilized batch dark fermentation

The objective of the study was to select microorganism support particle to enhance hydrogen production in an immobilized system by dark fermentation. Stainless steel scrubber, volcanic stone, tulle, polyester fiber, loofah sponge, plastic bath sponge, sea sponge and aquarium biological sponges were used as support materials to investigate hydrogen production potentials of these particles. Waste wheat was the substrate and it was hydrolyzed in diluted sulfuric acid at high temperature to obtain sugar solution. Heat and acid pretreatment method was applied to anaerobic sludge to eliminate methanogens and to select spore forming hydrogen producing bacteria like Clostridium sp. Experiments were conducted at different initial total sugar concentrations TS0 = 13 ± 1 g/L, 17 ± 1 g/L, 27 ± 3 g/L under thermophilic conditions (55 °C) for all particle types. The highest hydrogen yield (YH2 = 1.96 mol H2/mol glucose) and maximum hydrogen production rate (HPR = 7.39 ml H2/h) were obtained with polyester fiber particles at TS0 = 13 ± 1 g/L. The particle size of polyester fiber was varied between Dp = 0.5-3 cm at TS0 = 13 ± 1 g/L. The highest production yield of 1.96 mol H2/mol glucose was obtained with particle size of Dp = 1.5 cm. The results indicated that polyester fiber can be used as microorganism support particle for hydrogen production in immobilized bioprocesses.