Analysis of B. subtilis biofilm metabolism at gene expression level. The hypothesis tested in the present study was that extracellular pH and environmental buffer influence the biofilm development. Results provide important information of the response of biofilms to changes in extracellular pH. Overall design: Total RNA obtained from B. subtilis NCIB 3610 WT or ?alsS mutant biofoilms grown on MSgg with 1 mM MOPS (minimally buffered) at 24 or 36 h compared to NCIB 3610 WT or ?alsS mutant biofoilms grown on MSgg with 100 mM MOPS (buffered) at 24 or 36 h