纤维素酶添加时间对碱性双氧水预处理玉米秸秆高温厌氧消化的影响

研究了纤维素酶添加时间对玉米秸秆高温厌氧消化的影响。玉米秸秆首先进行碱性双氧水预处理,结果表明,预处理最佳条件为NaOH投加量4 g/L,H2O2投加量17 g/L,固液比1:40,预处理时间4 h。预处理后的玉米秸秆在50℃下进行序批式高温厌氧消化,分别在发酵前期(第1天)、发酵中期(第10天)和发酵后期(第20天)向系统中添加15 mL(20 FPU/g)纤维素酶液。结果表明,添加纤维素酶能有效促进厌氧发酵过程中的生物质水解,对随后产酸产甲烷过程的直接影响较小。和对照组相比,发酵前期、中期和后期添加纤维素酶时系统的累积产气量分别提高18.66%、10.39%和1.93%,VS转化率分别提高13.51%、8.00%和2.90%。前期、中期和后期添加纤维素酶均能提高厌氧消化产气,但厌氧消化前期添加纤维素酶效果更为明显。

Effect of cellulase addition time on thermophilic anaerobic digestion of corn stovers pretreated with alkaline hydrogen peroxide

In this study, we examined the effect of cellulase addition time on the thermophilic anaerobic digestion of corn stovers.First, parameters of alkaline hydrogen peroxide pretreatment of corn stovers, including NaOH dosage (4 g/L), H2O2 dosage (17 g/L), solid-to-liquid ratio (1:40), and pretreatment time (4 h), were optimized.The pretreated corn stovers were anaerobically digested at 50℃ in batch experiments.Next, 15 mL(20 FPU/g) cellulase was added to the system on days 1, 10, and 20.Cellulase addition effectively improved biomass hydrolysis during fermentation but exerted a weaker effect on subsequent acidogenesis and methanogenesis.Compared with control, cumulative biogas production after cellulase addition on days 1, 10, and 20 increased by 18.66%, 10.39%, and 1.93%, respectively, and VS conversion rate increased by 13.51%, 8.00%, and 2.90%, respectively.Thus, our results indicated that addition of cellulase at any time improved biogas production;however, this effect was more obvious at the beginning of fermentation.