Seaweed fermentation- Preventing anaerobic processes after aerobic decomposition

I'm in the process of aerobically-decomposing A. Nodasum meal with select bacteria. After I have got it how I want it, how do I preserve it from producing hydrogen sulphide and other noxious gases when I put it in air-tight containers? Freezing is an option, but not really practical. Production capacity is about 10L at time. Happy to add details as required. The critters are:

i've also ordered a B. Subtilis preparation for breaking down cellulose in addition. Will these make a useful amount of aliginate lyase to do the job? I can't afford the enzyme on its own - Sigma-Aldrich stuff.. Are there other methods to degrade the alginate? I never realised that seaweed was composed of little jelly-like sacs. pH target is 8 and 30c temps. I'm decomposing 2.5kg A. Nodasum in 10L. I'll be using it to buffer and charge biochar, which I will also be making.