Biotechnological conversion processes involving gases (derived from residues) are often limited by challenges such as (i) poor mass transfer characteristics (rate-limiting) particularly due to low solubility of relevant gases (ii) safety issues with certain gases (iii) presence of impurities in the gas streams (iv) a limited understanding of the design and scale-up of gas-based systems. This project aims to overcome these obstacles with new bioreactor designs involving membranes and to undertake scale-up and techno-economic analysis of these novel process.