Isolation and characterization of R̲h̲o̲d̲o̲c̲o̲c̲c̲u̲s̲ Sp. strain IGTS8 promoters and functional analysis of 16S rRNA promoters from R̲h̲o̲d̲o̲c̲o̲c̲c̲u̲s̲ and E̲. C̲o̲l̲i̲ in homologous and heterologous systems