Abstract:

Cellulase is a key enzyme for cellulose degradation. In order to enhance the efficiency of cellulose degradation,
two different cellulase genes were fused and integrated into Lactobacillus genome, and efficiently expressed. Two pairs
of primes were designed according to two cellulose genes in GenBank, a peptide containing 10 amid acids was inserted
between the two genes. CelL15 and CelL73 were amplified by PCR method, and then fused and cloned into the expression
vector pMJ67. The recombinant vector was electrotransferred into Lactobacillus casei. SDS-PAGE analysis showed that the
fusion cellulase protein was successfully expressed and secreted into the cell culture supernatant, which was approximately
83 kD. Enzyme activity detection on solid medium indicated that the recombinant Lactobacillus could obviously degrade
sodium carboxymethylcellulose in the medium, and the cellulase activity in the supernatant was up to 1.25 U/mL after
culture for 36 h.

Key words: cellulase, recombinant Lactobacillus, fusion, secretion