The production of duckweed as a source of biofuels

Duckweed is a promising feedstock for the production of biofuels. Advantageous characteristics include rapid, clonal growth as small free-floating plants on nutrient-rich water; global adaptability across a broad range of climates; naturally high protein content; and inducible high starch content with low or no lignin, which enables other value-added products. The objective of this article is to review the published research on duckweed cultivation in nutrient-rich wastewaters, starch enrichment in duckweed plants and conversion of high-starch duckweed to biofuels. Duckweed yields of 39.1-105.9 t ha(-1) year(-1) have been achieved using wastewater as the nutrient source, which are much higher than the yields of most other potential energy crops. Duckweed starch contents of 31.0-45.8% dry weight have been achieved after it has been subjected to nutrient starvation for 5-10 days, and up to 94.7% of the starch could be converted to ethanol using the existing technologies for corn starch conversion. Future research objectives include selecting high-performance duckweed strains, improving starch enrichment and conversion, and developing technologies for large-scale operations.