Enzymatic Hydrogen Production:  Conversion of Renewable Resources for Energy Production

Abstract

Using the enzymes glucose dehydrogenase (GDH) and hydrogenase, we have shown that a variety of sugars that are components of renewable resources can be enzymatically converted to molecular hydrogen. The rates at which hydrogen was evolved paralleled the substrate specificity of GDH. The highest rate of hydrogen production measured was 97.8 μmol/h, and the stoichiometric yield of hydrogen was 98% with 50 mM glucose as the substrate. Lactose, sucrose, cellulose, xylan, steam-exploded aspen wood, and starch also served as substrates for hydrogen production when the corresponding enzymes were included in the reaction mixture to generate the appropriate monosaccharide for which GDH has specificity. The data obtained are discussed in the context of the rate-limiting steps of hydrogen production from renewable sugar and the possible applications of enzymatic hydrogen production.

High‐Yield Production of Dihydrogen from Xylose by Using a Synthetic Enzyme Cascade in a Cell‐Free System

“…The experiments were carried out in a continuous‐flow system, which was purged with ultrapure nitrogen (Airgas) 12. 14 H 2 evolution was detected with a tin oxide thermal conductivity sensor (Figaro TGS 822, Osaka, Japan) that was previously calibrated with in‐line flow‐controllers and ultrapure hydrogen.…”

“…Enzymatic H 2 production in vitro from a glucose was first achieved by Woodward and co‐workers using glucose dehydrogenase and hydrogenase 11. Enzymatic H 2 generation based on xylose was also reported, but the yield was very low, only 0.53 moles of H 2 per mole of xylose 12. To efficiently release all of the chemical energy stored in glucose, glucose‐6‐phosphate (G6P) and eleven enzymes were combined and these generated almost the theoretical yield (11.6/12.0) of H 2 from G6P 4.…”

Asymmetric Reduction of α‐Keto Esters with Thermus thermophilus NADH‐Dependent Carbonyl Reductase using Glucose Dehydrogenase and Alcohol Dehydrogenase for Cofactor Regeneration

“…The optimal pH for the reduction reaction catalyzed by TtADH is approximately 6.0 [14] and that for glucose oxidation catalysed by TaGDH is 7.0. [16] Due to the instability of the reduced cofactor under acidic conditions, neutral pH was chosen as a compromise taking into account cofactor stability and TtADH activity at suboptimal pHs. Nevertheless, TaGDH retains full catalytic activity after 9 h at 55°C, [17] while TtADH is highly efficient and selective at 50°C.…”

A multianalyte flow electrochemical cell: application to the simultaneous determination of carbohydrates based on bioelectrocatalytic detection

“…Instead, glucose dehydrogenase from the thermoacidophilic archaebacterium T. acidophilum (Smith et al, 1989) was chosen for this work for reasons explained below. This enzyme is a NAD(P) + /NAD(P)H dependent dehydrogenase having catalytic activity not only for glucose but also for galactose and xylose (Smith et al, 1989;Woodward et al, 2000). As seen in Table 2, GDH from T. acidophilum was successfully mediated by the osphendione mediator resulting in a K app m of 68 mM for galactose.…”