Selection of microorganism immobilization particle for dark fermentative biohydrogen production by repeated batch operation

The objective of this study was to evaluate the hydrogen production potentials of different microbial support particles namely; plastic scouring sponge pad, plastic nylon sponge, black porous sponge, plastic scouring sponge pad with metal mesh, plastic nylon sponge with metal mesh to be used in an immobilized bioprocess system. The experiments were conducted in repeated batch mode at retention times between 1 and 5 day. The substrate was waste wheat which was sieved down to 70 μm size (less than 200 mesh) first and then, hydrolyzed by using H2SO4 at pH = 2 and 90 °C in an autoclave for 15 min. The sugar solution obtained from hydrolysis of waste wheat was used as substrate after neutralization and nutrient addition. Hydrogen production potentials of different particles were evaluated through cumulative hydrogen volume and hydrogen production yield. Control experiments without particles were conducted in parallel to the experiments with particles to evaluate the effect of immobilization on production. The yield of production increased with decreasing retention time from 5 day to 1 day for all particles. The highest yield was achieved as 2.1 mol/mol glucose with metal mesh covered plastic scouring sponge pad at 1 day retention time repeated batch operation.