Methanisation of spent maqui berry pomace via enzymatic treatment

Abstract

The commercial enzyme preparations Pectinex Ultra SP-L and Celluclast 1.5 L were used in the treatment of spent maqui berry pomace to improve the anaerobic methanogenic potential of the pomace. Two types of enzymatic treatment were evaluated, a pre-treatment prior to anaerobic methanisation and an enzymatic treatment during the methanisation process itself. Neither of the commercial enzyme preparations significantly improved the methanogenic potential when the enzymes were used for pre-treatment. However, methane production was observed to increase by 28% when the Pectinex Ultra SP-L enzyme preparation was used during the methanisation process compared with that of samples that were not treated with any enzymes. Both enzymatic preparations showed an increase in glucose content, yielding a 132% increase in glucose content when the Pectinex Ultra SP-L preparation was used and a 102% increase when the Celluclast 1.5 L preparation was used. Finally, the addition of Pectinex Ultra SP-L increased the solubilised material content by 24–34%, whereas the addition of Celluclast 1.5 L achieved a 34% increase in solubilisation when 2 mg of enzyme was added per gram of total solids; however, there was no significant improvement observed when the Celluclast 1.5 L was added at other ratios.