Search

Rice plants are known to accumulate starch in leaf sheaths and culms, and in some cultivars significant amounts of starch are present at the mature stage. This can be considered as potential feedstock for the recovery of fermentable sugars. We isolated starches from the culms of cultivars Yumeaoba, Koshihikari, and Leafstar to investigate their structural and physical features. Yumeaoba culm starch contained 20.2% amylose, whereas Koshihikari and Leafstar contained 25.8% and 25.2%. Yumeaoba culm starch was found by chain-length distribution analysis to contain higher amounts of short chains, resulting in lower gelatinization temperature by 7 degrees C, as compared to Koshihikari and Leafstar. Consequently, the rate of enzymatic hydrolysis of Yumeaoba culm starches reached maximum at a lower temperature than Leafstar. Rice culm starch, with a lower gelatinization temperature, can provide an advantageous material for feedstock for bioethanol production in terms of energy conservation.

フレール型の専用収穫機と自走式ベールラッパ各1台による作業体系を想定して簡易なシミュレーションモデルを開発し，飼料イネのダイレクト収穫における作業時間の短縮・効率化の方策を検討した．1） 開発したモデルは，作業経路シミュレーションと作業時間シミュレーションの2つのモジュールで構成され，圃場区画や作物密度，作業経路等の条件設定値を変えた様々なシミュレーションが可能となった．2）実作業の作業時間解析を行い作業機の固有作業能率等のデータ収集を行った．この結果を用いて，圃場内でのロールベール運搬に関する両機の分担・連携条件と作業の効率化について解析が可能となった．3） 開発した本モデルは，表計算ワークシートとマクロプログラムで構成されるため，解析の目的に応じてモデルの改良・拡張が容易である．

The major carbohydrates of rice straw samples were determined in order to evaluate the potential of using rice straw as a feedstock for ethanol production in Japan. Straw samples were harvested by cutting the plants at ground level when the grain was mature and immediately heating or chilling the samples. In all cases, significant amounts (62–303 g kg−1) of soft carbohydrates defined as consisting of glucose, fructose, sucrose, starch and β-1,3-1,4-glucan were detected, in addition to structural carbohydrates (cellulose and xylan). These results indicate that rice straw is a rich source of fermentable sugars from both soft carbohydrates and lignocellulosic portions of the cell wall.