Characterization of dual enzyme resulted from bicistronic expression of two β-glucanases in porcine cells

Many animal feed grains contain high β-glucan in the cell wall. Pigs do not secret β-glucanase to degrade the β-glucan in their feed. The indigestible β-glucan not only blocks the release of nutrients from the grain cell wall, but also increases the digesta viscosity in the gastrointestinal tract of pigs. Therefore, dietary β-glucan significantly inhibits nutrient digestion and absorption in pigs. Transgenic expression of β-glucanase in the digestive tract of pigs may offer a solution to solve this problem. In the current study, four artificial codon-optimized β-glucanases genes was prepared and expressed in porcine cells. Only p Bg A and p Egx showed high activity in transfected pig kidney cells. To improve the p H range and p H stability of β-glucanase, the two β-glucanases, p Bg A and p Egx, were co-expressed in pig kidney cells and salivary gland cells by Linker A3 or 2A peptide. The resulting dual enzymes of p Bg A3 p Eg and p Bg2 Ap Eg showed significantly enlarged p H range and significantly increased p H stability, as compared to parental enzymes. These results provide useful data for future study on increasing the feed digestibility of pigs by transgenic expression of β-glucanase in their salivary glands.