Biohydrogen production from starch processing wastewater in this study resulted the highest yield of 61.75 mL H 2 /g COD at initial pH 7.0, thermophilic temperature, and iron concentration 800 mg Fe/L. The yield was 2-folded higher than the operation at mesophilic temperature or without iron addition. Cell immobilization by addition of biomaterials (BM) could improve the hydrogen yield by 2-folded comparing to the non-addition. BM from plants (loofa sponge) was found producing higher yield than that from animals (silk cocoon), and optimal concentration of BM was 5% (V/V). Furthermore, it was revealed further inside its ecosystem using SEM, 16S rDNA sequencing and FISH.There was found rod-shaped microorganisms of Bacillus cereus, which reported as efficient starch-utilizing hydrogen producers, was dominant in the system with population of 47% of all specie identified.