An in silico re-design of the metabolism in Thermotoga maritima for increased biohydrogen production

Microbial hydrogen production is currently hampered by lack of efficiency. We examine
how hydrogen production in the hyperthermophilic bacterium Thermotoga maritima can be
increased in silico. An updated genome-scale metabolic model of T. maritima was used to i)
describe in detail the H2 metabolism in this bacterium, ii) identify suitable carbon sources
for enhancing H2 production, and iii) to design knockout strains, which increased the in
silico hydrogen production up to 20%. A novel synthetic oxidative module was further
designed, which connects the cellular NADPH and ferredoxin pools by inserting into the
model a NADPH-ferredoxin reductase. We then combined this in silico knock-in strain with
a knockout strain design, resulting in an in silico production strain with a predicted 125%
increase in hydrogen yield. The in silico strains designs presented here may serve as
blueprints for future metabolic engineering efforts of T. maritima.