In accordance with one embodiment, a mixture for forming polymer-encapsulated whole cells includes: at least one polymer precursor; at least one initiator; and a plurality of whole cells. In further embodiments, a product includes a structure comprising a plurality of whole cells encapsulated by a polymer network, where polymer(s) of the polymer network are cross-linked. The whole cells may include live whole cells, dried whole cells, and/or reconstituted whole cells, and have a characteristic to convert a chemical reactant to a product, where the chemical reactant is a gas (e.g., C1-C3 carbon gases such as methane, carbon dioxide, ethane, etc.) and the product is a liquid (e.g. methanol, etc.). For example, the whole cells may include organisms such as methanotrophic organisms and/or acetogenic anaerobes.