Wasoontharawat Metinee, Jantama Sirima Suvarnakuta, Kanchanatawee Sunthorn, Jantama Kaemwich
Metabolic Engineering Research Unit, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, 111 University Avenue, Suranaree, Muang, Nakhon Ratchasima, 30000, Thailand.
Faculty of Science, Udon Thani Rhajabat University, 64 Taharn Road, Muang, 41000, Thailand.
Bioprocess Biosyst Eng. 2016 Nov;39(11):1775-84. doi: 10.1007/s00449-016-1652-3. Epub 2016 Jul 20.
Rice straw (RS) may serve as a low-cost biomass for the production of biofuels and biochemicals, but its native structure is resistant to enzymatic and microbial deconstruction. Therefore, an efficient pre-treatment method is required to modify crystalline cellulose to a more reactive amorphous form. This work investigated pre-treatments of rice straw involving size reduction (S) followed by either sodium hydroxide (NaOH) or diluted sulfuric acid (H2SO4) and liquid hot water (LHW). The shrinkage of the vascular bundles in the rice straw structure pre-treated with NaOH-LHW-S was higher than that with LHW-S and H2SO4-LHW-S pre-treatments. The highest levels of total fermentative products and residual sugars were obtained at the concentrations of 7.8 ± 0.2 and 2.1 ± 0.3 g/L, respectively, after fermentation by Clostridium cellulolyticum for NaOH-LHW-S pre-treated rice straw at 121 °C for 120 min. Overall, the combined physicochemical pre-treatment of RS led to improved microbial hydrolysis during cellulose degradation at the percentage of 85.5 ± 0.5.
稻草（RS）可作为生产生物燃料和生物化学品的低成本生物质，但它的天然结构对酶解和微生物分解具有抗性。因此，需要一种有效的预处理方法将结晶纤维素转化为更具反应性的无定形形式。本研究考察了稻草的预处理方法，包括先进行尺寸减小（S），然后分别用氢氧化钠（NaOH）或稀硫酸（H₂SO₄）以及液态热水（LHW）处理。经NaOH-LHW-S预处理的稻草结构中维管束的收缩程度高于经LHW-S和H₂SO₄-LHW-S预处理的情况。在用溶纤梭菌于121℃对经NaOH-LHW-S预处理的稻草进行120分钟发酵后，总发酵产物和残余糖的最高水平分别为7.8±0.2克/升和2.1±0.3克/升。总体而言，稻草的联合物理化学预处理使纤维素降解过程中的微生物水解得到改善，水解率为85.5±0.5%。
