Fig. 2

Detection of recombinant His-tagged GH16A, GH16B, GH16C, and GH16D β-agarases expressed in Escherichia coli on LB agarose plates and on SDS-polyacrylamide gels. a Transformants expressing individual recombinant His-tagged β-agarases were spotted onto LB agarose plates (1.5%[w/v] agarose, 0.1 mM IPTG, 50 µg/mL chloramphenicol, and 25 µg/mL kanamycin) and incubated for 3 days at 37 °C. To visualize the enzymatic activity as a clear zone, plates were stained with Lugol’s iodine at 25 °C. b Total, soluble supernatant (Sup), and insoluble inclusion (Pellet) intracellular fractions as well as culture supernatants (CS) as extracellular fractions were prepared from E. coli transformants cultured in the presence of 0.5 mM IPTG. Equivalent amounts of each portion were subjected to SDS–PAGE. Representative results are shown; two additional experiments yielded similar results