The characteristics of waste composition also affected kinetic of
the biological processes. Mix 1 showed the highest values for production
rate in both hydrogen and methane production tests. On
the contrary, Mix 2 characterised by higher lipid content, showed
the lowest rates, again both for H2 and CH4 production. This effect
may be related to lower hydrolysis rate for the two types of organic
substances, carbohydrates and lipids. As reported by Christ et al.
(2000) and by Dong et al. (2011), lipids are characterised by the
slowest hydrolysis rates while carbohydrates by the fastest. The
large presence of these two groups of organics due to different
waste compositions also produced an impact on the overall rate
of hydrogen and methane production.