We constructed a new Thermus thermophilus cloning vector which enables the colour selection of cloned DNA inserts in the T. thermophilus HB27 host strain (β-gal) on growth plates containing 3,4-cyclohexenoesculetin β- d-galactopyranoside (S-gal) in the medium. This vector harbors a modified β-galactosidase gene (TTP0042 of T. thermophilus HB27) with 12 unique restriction enzyme sites ( Acc65I, AvrII, BlpI, BssHII, EcoRI, EcoRV, HindIII, NruI, SalI, SpeI, SphI and XbaI) as multiple cloning sites under the control of the T. thermophilus slpA promoter. This host-vector system facilitates cloning procedures in T. thermophilus HB27. [ABSTRACT FROM AUTHOR]