Patent ID: 8048674

Claim:
A method of evolving a biocatalytic activity of a cell, comprising: (a) recombining at least a first and a second DNA segment from at least one gene conferring ability to catalyze a reaction of interest by conducting a multi-cyclic polynucleotide extension process on at least partially annealed polynucleotide strands having sequences from the first and the second DNA segment, the first and the second DNA segment differing from each other in at least two nucleotides, to produce a library of recombinant genes, wherein the reaction of interest is the metabolism of cellulose; and (b) screening at least one recombinant gene from the library that confers enhanced ability to catalyze the reaction of interest by the cell relative to a wildtype form of the gene, wherein at least one of the first and the second DNA segment is produced by performing mutagenesis on one or more DNA molecules.