초록
<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P>The hard cell wall of some microalgae hampers efficient methane production when using those substrates. The present study investigated the effect of two groups of biocatalysts, namely carbohydrases and proteases, applied to <I>Chlorella vulgaris</I> and <I>Scenedesmus</I> sp. for microalgae hydrolysis prior to anaerobic digestion.</P><P><B>RESULTS</B></P><P><I>Chlorella vulgaris</I> subjected to protease activity resulted in higher organic matter solubilisation (47%) than the carbohydrase treated samples (25–29%). Out of the carbohydrases tested, maximum carbohydrate solubilisation was reached by applying Viscozyme (84% for <I>C. vulgaris</I> and 36% for <I>Scenedesmus</I> sp.). The anaerobic digestion assays revealed that biomasses hydrolyzed with protease reached the highest methane yield. In spite of the different macromolecular composition and behavior towards the biocatalysts, protease hydrolysis before anaerobic digestion enhanced methane yield 1.72‐fold and 1.53‐fold for <I>C. vulgaris</I> and <I>Scenedesmus</I> sp., respectively.</P><P><B>CONCLUSION</B></P><P>Despite the common belief that carbohydrates are responsible for the low digestibility of microalgae, this study suggested that proteins were the main polymers hampering anaerobic digestion. The addition of enzymes to enhance anaerobic digestibility could be questionable economically‐wise, however this investigation gives crucial information to elucidate the polymeric composition of two of the most common microalgae, <I>C. vulgaris</I> and <I>Scenedesmus</I> sp. © 2015 Society of Chemical Industry</P>