Table 1.

Bacterial strains and plasmids used in this study

Strain	Relevant characteristics	Reference
E. coli
DH10B	Cloning host	Invitrogen™
BL21 (DE3)	Expression host	Invitrogen™
Bifidobacterium
B. bifidum S17	intestinal isolate from a breast-fed infant	[23]
B. bifidum S16	intestinal isolate from a breast-fed infant	[23]
B. bifidum NCC189		NCC
B. bifidum NCIMB41171		NCIMB
B. breve S27	intestinal isolate from a breast-fed infant	This study
B. breve DSM20213	type strain, intestinal isolate from an infant	DSMZ
B. longum/infantis E18	intestinal isolate from an adult	[23]
B. longum/infantis NCC200		NCC
B. longum NCC2705	type strain	NCC
B. longum DSM20219	type strain, intestinal isolate from an adult	DSMZ
B. adolescentis NCC251	type strain	NCC
B. adolescentis DSM20083	type strain, intestinal isolate from an adult	DSMZ
B. lactis NCC362	type strain	NCC
B. lactis L15	isolate from a commercial dairy product	This study
B. animalis MB254	type strain	[23]
Plasmids
pMDY23	E. coli-Bifidobacterium shuttle vector harbouring the gusA reporter gene, Spcr	[33]
pMGS_PBAD_bopAHis6	pMGS containing bopA under control of arabinose-inducible PBAD promoter	This study
pMGS_Pgap_bopAHis6	pMGS containing bopA under control of constitutive Pgap promoter	This study