Abstract

Rice straw is an important feedstock for second-generation biorefineries, the majority being conventional white rice. This research investigated the potential of the straw of black rice Chakhao Poireiton, a rice variety of increasing importance, for biorefining. Pre-treatment of black rice straw was carried out in a pressurised microwave reactor and free sugar release was measured following digestion with Cellic® CTec3. This was compared to white rice straw. Pre-treatment (100 − 200° C for 5 min) did not drastically impact the sugar composition but brought about an enhanced release of glucose after enzymatic hydrolysis from 25 to 50% (black rice) and from 26 to 55% (white rice). For xylose digestibility, the increase was around seven-fold for black rice (8 to 57%) and five-fold for white rice (13 to 64%). This improvement in digestibility of the straw samples could have come from modification in the lignocellulose structural features making the polysaccharides more susceptible to hydrolysis. Black rice could be a suitable feedstock for a combined biorefinery – food and nutraceuticals from grain (much higher than white rice) and the straw for fermentable sugars comparable to white rice straw for biofuels.

摘要

稻草是第二代生物精炼厂的重要原料，主要是传统的白米。这项研究调查了黑米稻草Chakhao Poireiton的潜力，一种对生物精炼越来越重要的大米品种。黑米秸秆的预处理在加压微波反应器中进行，并在用 Cellic® CTec3 消化后测量游离糖释放。这与白稻草相比。预处理（100 - 200°C 5 分钟）不会显着影响糖的组成，但在酶水解后导致葡萄糖的释放增加，从 25% 到 50%（黑米）和从 26% 到 55%（白米） . 对于木糖消化率，黑米增加了约 7 倍（8% 至 57%），白米增加了 5 倍（13% 至 64%）。秸秆样品消化率的这种提高可能来自木质纤维素结构特征的改变，使多糖更容易水解。