Nanobioreactor designed to improve sustainable bioenergy production

Published in Nature Communications, the study shows how bacterial protein ‘cages’ can be reprogrammed as a nanobioreactor for hydrogen production. The carboxysome is a specialised bacterial organelle that encapsulates the CO2-fixing enzyme Rubisco into a virus-like protein shell.

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The naturally designed architecture, semi-permeability and catalytic improvement of carboxysomes have inspired the rational design and engineering of new nanomaterials to incorporate different enzymes into the shell for enhanced catalytic performance.

Researchers installed specific genetic elements into the industrial bacterium E. coli to produce empty carboxysome shells, identifying a small ‘linker’ (called an encapsulation peptide) capable of directing external proteins into the shell. The team developed methods to incorporate catalytically active hydrogenases (enzymes that catalyse the generation and conversion of hydrogen) into the empty shell, and through testing the hydrogen-production activities of the bacterial cells and the biochemically isolated nanobioreactors, found that the nanobioreactor achieved a 550 per cent improvement in hydrogen-production efficiency.