Fig. 1.

Heterologous synthesis of CelA in E. coli and synthesis/secretion in S. lividans. a CelA_His6 was synthesized in BL21 (DE3) cells. Expression of CelA_His6 carried on a pET vector was induced by 0.2 mM IPTG for 3 h at 30 °C. b Synthesis in and secretion of CelA from S. lividans. Polypeptides (1–8 µg/lane) from culture supernatants (~ 0.1 mL) that is equivalent to 0.2 mg of dry cell mass. The samples from cells grown for 2 days in the indicated media (see “Methods”) were harvested by precipitation with TCA (25%), analyzed by SDS-PAGE and stained with Coomassie blue. Lane 1, molecular weight markers: β-galactosidase (116 kDa), bovine serum albumin (66.2 kDa), ovalbumin (45 kDa), lactate dehydrogenase (35 kDa), restriction endonuclease Bsp98I (25 kDa), β-lactoglobulin (18.4 kDa), lysozyme (14.4 kDa). Pha, phage medium; NB, nutrient broth; NB_2X, nutrient broth double strength; MM, minimal medium; C₅ and C₁₅, casamino acids (5 or 15 g/L); TSB, tryptic soy broth; Ben, Bennet medium