(421as) Evaluation Kenaf As a Renewable Source for Green Chemicals and Fuels

Authors: 
Kamireddy, S. R., University of North Dakota
Ji, Y., University of North Dakota


Kenaf (known as Hibiscus Cannabis) is a plant belongs to the Malvaceae family. It is a fiber crop mainly used in the pulp and paper industry across the globe. It can grow up to 10 to 12 ft high. Kenaf can yield highest amount of biomass per acre, approximately around 10 to 15 tons. The objective of this project was to increase the conversion yield of fermentable sugars in the Kenaf by dilute sulfuric acid pretreatment and enzymatic hydrolysis.

Raw kenaf was pulverized using Wiley mill to an approximate particle size of about 0.1 to 0.5 mm. Extractives were removed by both water extraction and ethanol extraction using Soxhlet apparatus.  Compositional analysis on extractive free kenaf was determined by NREL/TP-510-42618. A Design of Experiments was formulated on kenaf biomass with three independent variables, 1) sulfuric acid concentration (0.5, 1.0 and 2%) and 2) reaction time (10, 15 and 20 minutes) and 3) reaction temperature (140, 150 and 160°C).  The pretreatment was performed by steam jacketted batch reactor fabricated by Autoclave Engineers Inc. Monomeric sugars and Total sugars were analyzed by Agilent 1200 series HPLC based on NREL LAP. Acid soluble lignin content was measured by Thermo Scientific Evolution 600 UV-VIS spectroscopy. Enzymatic hydrolysis was conducted according to NREL/TP-510-42629. The enzymes used for analysis were Accellerase 1500 supplied by Genencor.  The enzyme loading was kept constant 20mg of protein/gram of cellulose. The reaction time was 72 hours and reaction temperature was 50 °C. The pretreatment yield and glucose yield after the enzymatic hydrolysis showed that kenaf is a potential feedstock for biofuel production.