The Effect of Enzyme Addition
on the Anaerobic Digestion of Food Waste
Mariani Rajin, Abu Zahrim Yaser, Sariah Saalah, Yogananthini Jagadeson
and Marhaini Ag Duraim
Abstract Due to increase in the amount of food waste, the proper method to dispose food waste has become a concern. Anaerobic digestion has received increasing
attention because of its advantages such as reducing waste pollution and producing
clean energy. Hydrolysis, the first step in anaerobic digestion, has been identified as
rate-limiting step in this process. Enzyme addition during hydrolysis of a substrate
has been reported as a promising alternative to stimulate waste degradation, thus
improving the efficiency of the anaerobic digestion system. In this work, Candida
Antarctica Lipase B (CALB) was used to facilitate the anaerobic digestion of food
waste for 40 days. The effects of lipase addition on the total organic carbon (TOC),
biogas production, pH, electrical conductivity and moisture content were studied.
The finding showed that the food waste digestion with lipase achieved higher reduction in pH at a shorter time, indicating a higher degradation rate when lipase was
added into the system. However, lipase addition had no effect on the final values
of both pH and conductivity after 40 days of digestion. It was also found that the
usage of lipase in this study did not help in increasing the biogas production due to
acidification of food waste during digestion that inhibited the biogas production. On
the other hand, it was found that the final moisture content of 88% achieved by food
waste with lipase was higher as compared to the control sample. The finding also
showed that higher reduction in TOC value was achieved when lipase was added
into the digestion system, showing higher degradation rate by microorganisms. The
complex molecule in food waste was hydrolysed to a simple molecule assisted by
the enzyme added so that it can be easily utilised by the microorganisms.
Keywords Anaerobic digestion · Lipase · Hydrolysis · Physiochemical
properties · Biogas
M. Rajin (B) · A. Z. Yaser · S. Saalah · Y. Jagadeson · M. Ag Duraim
Chemical Engineering Programme, Faculty of Engineering, Universiti Malaysia Sabah, Jalan
UMS, 88400 Kota Kinabalu, Sabah, Malaysia
e-mail: mariani@ums.edu.my
S. Saalah
e-mail: s_sariah@ums.edu.my
© Springer Nature Singapore Pte Ltd. 2020
A. Z. Yaser (ed.), Green Engineering for Campus Sustainability,
https://doi.org/10.1007/978-981-13-7260-5_9
119
on the Anaerobic Digestion of Food Waste
Mariani Rajin, Abu Zahrim Yaser, Sariah Saalah, Yogananthini Jagadeson
and Marhaini Ag Duraim
Abstract Due to increase in the amount of food waste, the proper method to dispose food waste has become a concern. Anaerobic digestion has received increasing
attention because of its advantages such as reducing waste pollution and producing
clean energy. Hydrolysis, the first step in anaerobic digestion, has been identified as
rate-limiting step in this process. Enzyme addition during hydrolysis of a substrate
has been reported as a promising alternative to stimulate waste degradation, thus
improving the efficiency of the anaerobic digestion system. In this work, Candida
Antarctica Lipase B (CALB) was used to facilitate the anaerobic digestion of food
waste for 40 days. The effects of lipase addition on the total organic carbon (TOC),
biogas production, pH, electrical conductivity and moisture content were studied.
The finding showed that the food waste digestion with lipase achieved higher reduction in pH at a shorter time, indicating a higher degradation rate when lipase was
added into the system. However, lipase addition had no effect on the final values
of both pH and conductivity after 40 days of digestion. It was also found that the
usage of lipase in this study did not help in increasing the biogas production due to
acidification of food waste during digestion that inhibited the biogas production. On
the other hand, it was found that the final moisture content of 88% achieved by food
waste with lipase was higher as compared to the control sample. The finding also
showed that higher reduction in TOC value was achieved when lipase was added
into the digestion system, showing higher degradation rate by microorganisms. The
complex molecule in food waste was hydrolysed to a simple molecule assisted by
the enzyme added so that it can be easily utilised by the microorganisms.
Keywords Anaerobic digestion · Lipase · Hydrolysis · Physiochemical
properties · Biogas
M. Rajin (B) · A. Z. Yaser · S. Saalah · Y. Jagadeson · M. Ag Duraim
Chemical Engineering Programme, Faculty of Engineering, Universiti Malaysia Sabah, Jalan
UMS, 88400 Kota Kinabalu, Sabah, Malaysia
e-mail: mariani@ums.edu.my
S. Saalah
e-mail: s_sariah@ums.edu.my
© Springer Nature Singapore Pte Ltd. 2020
A. Z. Yaser (ed.), Green Engineering for Campus Sustainability,
https://doi.org/10.1007/978-981-13-7260-5_9
119