The present disclosure relates, in some aspects, to cell-free methods and systems for large-scale conversion of methane to isobutanol, comprising combining, in a bioreactor at elevated pressure, methane, oxygen, and cell lysates containing methane monooxygenase, methanol dehydrogenase, and enzymes that catalyze the conversion of formaldehyde to isobutanol, to form a cell-free reaction mixture, and incubating under suitable conditions the cell-free reaction to convert methane to isobutanol.

Quantum dots (QDs) and nanoplatelets (NPLs) are two types of nanoparticles used as scaffolds for enzymes operating in enzymatic cascades. Combinations of QDs and NPLs were surprisingly found to operate synergistically to create a greater enhancement than either alone when operating as scaffolds for enzymatic cascade reactions. A process involves providing an enzymatic cascade including a cluster of nanoparticles including both QDs and NPLs and having a plurality of enzymes bound thereto, the enzymes configured as an enzymatic cascade, such that the product of a first enzyme is a substrate of a second enzyme; contacting the cascade cluster with a substrate of the first enzyme; and allowing a reaction to proceed so that each of the plurality of enzymes acts in succession to produce an end product. The enzymes are bound to the nanoparticles via metal affinity coordination between histidine tags on the enzymes and zinc-containing surfaces of the nanoparticles.