Efficient production of a recombinant ι-carrageenase in Brevibacillus choshinensis using a new integrative vector for the preparation of ι-carrageenan oligosaccharides

•An integrative multicopy vector pBCGA used for B. choshinensis was developed.•The activity of the strain I24 could keep stable under antibiotic-free condition.•The ι-carrageenase acitivity of the strain I24 reached to 182.4 U/mL within 24 h.•The recombinant ι-carrageenase hydrolyzed ι-carrageenan via a processive mechanism.