In fact, cellulase activity of co-digestion with different mixture
ratios were in varying degrees of improvement compared with
individual straw fermentation with lowest cellulase activity and
individual FW fermentation with higher cellulase activity, which
illustrated that food waste promoted the role of straw (Fig. 2). On
the other hand, straw could be a good C/N balance in the reaction
system to avoid inhibition of gas production in individual FW
fermentation caused by high N content. Moreover, another
benefit of the mixture of FW and straw was to reduce the concentration
of Naþ and other cationic elements, which were reported
to have inhibitory effects on microorganisms in food
waste [26,31].