3.3. High-yield LA production by B. coagulans LA204 from five
lignocellulosic materials
The ability of B. coagulans LA204 to produce LA from five
different lignocellulosic materials was further examined. Five
percent (w/w) NaOH-pretreated (with subsequent washing) or
non-pretreated corn stover, wheat stover, rice stover, corncob
and miscanthus stover were used as carbon sources, and
10 g/L yeast extract was used as the nitrogen source; fermentation
were carried out at 50 C for 72 h with the addition of
cellulase at a concentration of 50 FPU/g stover. Subsequent to
fermentation, the LA titer was 14 and 27 g/L in non-pretreated
and pretreated corn stovers; the acetic acid concentration in
the culture was 10.5 and 8 g/L, respectively (Fig. 4). The LA
yields in pretreated and non-pretreated corn stover were 0.52
and 0.28 g/g stovers. LA production levels in pretreated and
non-pretreated wheat stover, rice stover, and corncob were
similar to that in corn stover (0.45–0.54 g/g stover for pretreated
stovers and 0.21–0.28 g/g stover for non-pretreated stovers).
Importantly, the LA titer in pretreated miscanthus stover medium
was 37.5 g/L and the yield reached 0.75 g/g stover (Fig. 4).
Although the yield and titer of LA produced from miscanthus
stover were much higher than that from agro stovers, agro
stovers are easily gathered after grain is harvested. Thus, B.
coagulans LA204 has strong potential for lignocellulosic LA
production.