hemicellulolytic bacteria , cellulolytic bacteria , hydrogen-producing acetogens , and acetate- and h ( 2 ) -plus-co ( 2 ) -utilizing methanogens were enumerated by the most-probable-number technique with media containing oat spelt xylan , ball-milled cellulose , butyrate , acetate , and h ( 2 ) plus co ( 2 ) , respectively .
C0020275
hydrogen
C0011744
h ( 2