Clostridium acetobutylicum

has been extensively exploited to produce biofuels and solvents and its biofilm could dramatically improve the productivities. However

genetic control of

C. acetobutylicum

biofilm has not been dissected so far. Here

to identify potential genes controlling

C. acetobutylicum

biofilm formation

over 40 gene candidates associated with extracellular matrix

cell surface

cell signaling or gene transcription

were tried to be disrupted to examine their individual impact. A total of 25 disruptants were finally obtained over years of attempts

for which biofilm and relevant phenotypes were characterized. Most of these disruptants formed robust biofilm still

or suffered both growth and biofilm defect. Only a strain with a disrupted histidine kinase gene (CA_C2730

designated

bfcK

in this study) abolished biofilm formation without impairing cell growth or solvent production. Further analysis revealed that

bfcK

could control flagellar biogenesis and cell motility at protein levels. The

bfcK

also appeared to repress the phosphorylation of a serine/threonine protein kinase (encoded by CA_C0404) that might negatively regulate biofilm formation. Based on these findings

possible

bfcK

-mediated mechanisms for biofilm formation were proposed. This is a big step toward understanding the biofilm formation in

C. acetobutylicum

and will help further engineering of its biofilm-based industrial processes.