2.1 Microorganisms and chemicals
Escherichia coli BL21(DE3)pLysS (Invitrogen) was purchased from
Thermo Fisher Scientific Japan (Tokyo, Japan). The pRSET-EmGFP bacterial
expression vector was purchased from Thermo Fisher Scientific Japan. The
vector pRSET-EmGFP was introduced to E. coli BL21(DE3)pLysS using
the standard method in the users’ manual. The strain was cultivated in
LB broth that included 10 g/L Bacto® Tryptone (Becton Dikinson and Co.
(BD) Japan, Tokyo, Japan), 5 g/L Bacto® yeast extract (BD), and 10 g/L
NaCl. The culture was incubated overnight at 37°C with shaking at 200
rpm. This was the inoculum used in the experiments. The culture broth
was stored as frozen stocks with 30% glycerol in a deep freezer at
−80°C. Experimental-grade yeast extracts were purchased from BD,
Millipore Sigma Japan (Tokyo, Japan), Kyokuto Pharmaceutical Industrial
Co. Ltd. (Tokyo, Japan), and Nihon Pharmaceutical Co. Ltd. (Tokyo,
Japan), and referred to as E1, E2, E3, and E4, respectively.
Manufacturing-grade yeast extracts were provided by manufacturers
including Oriental Yeast Co. Ltd. (Tokyo, Japan), Nihon Paper (Tokyo,
Japan), and named as M1, M2, M3, and M4.