Bioenergy potential of duckweed (Lemna gibba L.) biomass

ABSTRACT

This work illustrates the bioenergy potential of Lemna gibba cultivated on urban wastewater. A reactor (25 L) was established and changes in wastewater and duckweed characteristics were estimated at the end. The reactor showed relative growth rates (RGRs) of 7.47 g/m²d, 10.6 g/m²d, and 13.63 g/m²d after the 1st, 2nd, and 3rd weeks with chemical yield rate (g/m² d) of starch, protein, and lipid of 4.96, 7.68, and 1.90, respectively. The proximate analysis showed 10.03% moisture, 13.23% ash content, 63.96% volatile matter, and 14.73% fixed carbon. The elemental composition (%) of biomass was as follows: C = 41.67, H = 3.57, N = 3.67, S = 0.83, and O = 32.83. The dried biomass showed a high content (%) of energy molecules: total sugar (38.0), starch (24.5), and lipid (9.3). Gas chromatography of the extracted lipid presented high contents of C16:0-palmitic acid (37.68%), C18:2-linoleic acid (18.11%), and C18:3-linolenic acid (33.76%) in duckweed. Results suggested the potential of Lemna as feedstock for renewable energy operations.

KEYWORDS:

• HHV
• linoleic acid
• lipid
• palmitic acid
• starch