In Vivo Enzyme Entrapment in a Protein Crystal

Cry3Aa is a protein that forms crystals naturally in the bacterium Bacillus thuringiensis. Here we report that coexpression of Cry3Aa and a Proteus mirabilis lipase without recombinant fusion results in the efficient passive entrapment of the lipase within the nanoporous channels of the resulting crystals. This Cry3Aa crystal-mediated entrapment provides multiple benefits to the lipase including a high enzyme loading, significantly improved thermostability, increased proteolytic resistance, and the ability to be utilized as a recyclable biodiesel catalyst. These characteristics, along with its greatly simplified method of isolation, highlight the potential of Cry3Aa crystal-mediated enzyme entrapment for use in biocatalysis and other biotechnological applications.