# Gas fermentation reactors

Upstream — fermentation & cell culture — Specialized anaerobic bioreactors — tall column gas-lift vessels, hollow-fibre membrane cell-retention systems and multi-stage gas-cleaning trains — that let acetogenic bacteria convert steel-mill and refinery off-gases (CO, CO2, H2) into ethanol at industrial scale;

Source: https://en.bioecon.ru/market/upstream/gas-fermentation-reactors/