High-throughput determination of thioglycolic acid lignin from rice

For research and development of plants suitable for forage and biofuel production, the development of a highthroughput system of lignin determination, especially for herbaceous species, is important. However, currently available methods for lignin determination are not suitable for high-throughput analysis of herbaceous samples. In this paper, we describe a straightforward, high-throughput method for lignin determination as thioglycolic acid lignin from rice straw using disposable plastic microtubes, TissueLyser, and a UV microplate reader. We successfully plotted calibration curves derived from the readings of a spectrophotometer and a microplate reader using thioglycolic acid lignin prepared from bamboo milled wood lignin as a lignin standard. Based on the calibration curve, we could determine the lignin content in various organs from dried rice straw and rice seedlings. We confirmed that 20 mg of dried material from rice plants is adequate for stable determination of the lignin content. Using this method, 100 independent samples from rice straw can be analyzed in three days per person.