Development of a novel hybrid immobilization material (HY-IM) for fermentative biohydrogen production from beverage wastewater

A novel material (hybrid immobilization material, HY-IM) was developed by the combination of calcium-alginate, activated carbon (prepared from de-oiled jatropha waste), wako gel (silica gel) and chitosan for immobilization of hydrogen-producing bacteria. The stability of the prepared immobilized cells was evaluated by ten repetitive batch experimental runs; the cumulative hydrogen production from beverage wastewater during ten runs was in the range of 2865 to 3300 mL H₂/L. The Scanning electron microscopy (SEM) images of the HY-IM showed bacterial cells entrapment. The hydrogen production performance of the reactor with HY-IM (1.12 ± 0.04 mol H₂/mol hexose _utilized) was comparable to suspended cells reactor (1.07 ± 0.01 mol H₂/mol hexose_utilized), and demonstrated repeated usage of same HY-IM in the reactor with high stability. Experimental evidence suggests that HY-IM can be applied in continuous biohydrogen production from industrial wastewaters with high efficiency and stability. An efficient immobilization method was developed by the incorporation of eco-friendly synthesized activated carbon with chitosan and silica gel on calcium-alginate matrix (HY-IM). The HY-IM with immobilized cells was stable up to ten cycles of repetitive batch experiments and was able to produce 3.1 LH₂/L from beverage wastewater in comparison to 2.67 LH₂/L with suspended cells.