Bacillus subtilis 168 is unable to use sugars such as lactose, galactose, and xylose (11, 18) as its sole carbon source. This is surprising given the fact that genes which encode the proteins necessary for the degradation of lactose and xylose are present in B. subtilis and that these genes are expressed under inducing conditions (2, 4). For xylose it has been shown that this sugar is not transported inside the cell (14).