High Yield Production of Sugars from Deproteinated Palm Kernel Cake under Microwave Radiation via Dilute Sulfuric Acid Hydrolysis

Climate change together with the increased concern for the energy security has imparted a trend shifting on the use of fossil fuels to renewable energy sources. Worldwide attention has been focused on the transforming of agricultural waste into high value-added products. Malaysia, one of the global leading palm oil producers, seeking a next catalyst for sustaining economic growth since the palm oil production has reached a mature stage. Palm kernel cake (PKC), one of the main by-products from palm oil industry, is rich in protein (14.5 – 19.6%) and mannan (35.2%). It should be put under the spotlight and revolutionize into a source of revenue for oil palm industry. PKC composes of high carbohydrate contents, mainly hexoses such as mannose, glucose and galactose, which are the promising candidates for the production of bioethanol through fermentation by microorganism.

In Malaysia, approximately 2.39 million tons of palm kernel cake (PKC) was produced from palm oil mill annually. It consists of high carbohydrate contents, especially mannan (~35%). But, it was an under-utilized co-product of palm oil milling industry. Therefore, it is beneficial to amplify the potential applications for this biomass.

Miss Suet-Pin Fan, a PhD student, co-supervised by Dr. Chin-hua CHIA (National University of Malaysia) and Prof. Zhen FANG (Biomass Group, Xishuangbanna Tropical Botanical Garden, CAS) successfully used deproteined palm kernel cake as raw material for the production of monosaccharide under microwave radiation via dilute sulphuric acid hydrolysis.

In this work, it is the first time to systematically study the production of monosaccharides from deproteinated PKC (DPKC) via dilute sulfuric acid hydrolysis in a well-controlled microwave by response surface approach. DPKC under optimal operating conditions [170 °C, 0.181 N H2SO4 and substrate to solvent ratio (SS ratio), 1:40] offered a striking conversion with maximum yield of 77.11% of total monosaccharide in a reaction time period as short as 6 min 6 s and maximum mannose yield 92.11% obtained at 148 °C, 0.75 N H2SO4, 10 min 31 s and SS ratio of 1:49.69. From the results achieved in this study, it can be conclude that microwave-assisted hydrolysis is an efficient method in transforming the DPKC, an economically and environmentally benign source of fermentable carbohydrate into biofuels such as, 2,3-butanediol and hydrogen.


The study entitled “High Yield Production of Sugars from Deproteinated Palm Kernel Cake under Microwave Radiation via Dilute Sulfuric Acid Hydrolysis” has been published in Bioresource Technology, 2014, 153: 69-78,


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