碱处理与粒径大小对复合菌系MC1分解水稻秸秆性能的影响

Effect of Alkali Pretreatment and Particle Size on Rice Straw Decomposing Performance Using Composite Microbial System MC1

微生物技术是高效利用天然木质纤维素的主要途径,但预处理成本高和分解效率低已限制了该技术的广泛应用。文章以水稻秸秆和复合菌系MC1为试验材料,研究了碱处理对MC1分解稻杆性能的影响及其粒径大小(10 cm、5 cm和3 cm)对发酵液中氧浓度和稻杆分解率的影响。结果表明,稻杆粒径大小能调节发酵液中氧浓度,微好氧0.01~0.04 mg/L发酵条件有利于维持MC1对稻杆的高分解率。粒径为10 cm(高于培养液面)稻杆的减重率和木质纤维素成分的分解率显著高于(P<0.05)粒径为5 cm(浮于培养液面)和3 cm(低于培养液面)的处理。碱处理能提高MC1的分解速率,但对稻杆的最终分解程度没有明显影响。甲酸和乙酸是MC1分解稻杆产生挥发性脂肪酸的主要成分。

Microbial technology plays an important role in efficient utilization natural lignocellulosic biomass.However,the wide application of this technology has been limited by the problems of high pretreatment cost and low degradation rate.In this paper,rice straw and composite microbial system MC1(hereinafter referred to as“MC1”)were used as the main test materials,the effects of alkali pretreatment and different particle sizes(3 cm,5 cm and 10 cm)on rice straw decomposing performance and oxygen concentration of fermentation broth were evaluated.The results showed that particle size could control the oxygen concentration of fermentation broth,and the microaerobic condition of 0.01-0.04 mg/L was favorable to maintain the high degradation rate of rice straw with MC1.The weight-loss rate and the degradation rate of lignocellulosic compositions of rice straw at particle size of 10cm(higher than liquid culture level)was significantly higher(P<0.05)than that of the treatments with particle size of 5cm(floating liquid culture surface)and 3cm(lower than liquid culture level),respectively.Alkali pretreatment could shorten the decomposition period of MC1,but had no obvious influence on the final degradation rate of rice straw.Formic acid and acetic acid were the main components of volatile fatty acids produced by MC1 decomposing rice straw.