Compared with the results of Section 3.1, the PHA content was
far lower in the L-SFL (VFA-56%) than that in the S-SFL (VFA-100%)
(23.47–59.18%) while the CDW and X presented the opposite behavior (1.78–0.56 and 1.42–0.27 g/L). It has been reported that
the presence of degradable non-VFA organic substrates may have
dampened the FF selective pressure for PHA storing microorganisms,
resulted in low PHA productivity (Morgan-Sagastume et al.,
2010). Obviously, the existence of non-VFA organics resulted in a
relatively lower PHA content. The phenomenon was also observed
in the previous study (Jia et al., 2013).