Sulfur limitation increases duckweed starch accumulation without compromising growth

Abstract

Duckweeds contain relatively high levels of starch and are a potential biomass feedstock for biofuel production. Here, the biomass and starch yield of duckweed under three different nutrient-limited conditions were analyzed to investigate possible ways of further increasing the efficiency of starch production. The results showed that sulfur limitation resulted in the highest starch yield, which was 42% and 73% higher than in nitrogen or phosphorus limitation, respectively. The high yield of sulfur-limited duckweed is largely due to the combinations of little effects on biomass and high accumulations of starch. Although nitrogen limitation led to higher starch content (67.4%), it severely reduced biomass production. The photosynthetic performance indicator Fv/Fm was a simple and sensitive indicator of starch content in nutrient-limited duckweed. Taken together, this study demonstrates that sulfur limitation is a simple and efficient way to increase starch yield, highlighting the great potential of duckweed for biofuel production. We report that sulfur limitation is a practical approach to increase starch yields in duckweed without affecting growth or biomass.

Over-Expression of Phosphoserine Aminotransferase-Encoding Gene (AtPSAT1) Prompts Starch Accumulation in L. turionifera under Nitrogen Starvation

“…Considering their high multiplication rate, high starch content, and various other practical characteristics, they have been recognized as promising biofuel plants for the generation of hydrogen, ethanol, butanol, and biogas [ 1 , 2 , 3 ]. To date, many investigations have been carried out to improve the production of starch in duckweed fronds through the alteration of cultivation conditions, including temperature, light, hormones, supplication of plant growth regulators, nutritional starvation, or abiotic stresses [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Nitrogen starvation has been shown to be one of the key factors triggering the accumulation of starch in the fronds [ 5 , 16 , 17 ].…”