木薯渣在生物絮团处理养殖废水技术中的应用性研究

发布时间：2018-03-12 23:33

本文选题：酶解木薯渣　切入点：生物絮团　出处：《广西大学》2017年硕士论文　论文类型：学位论文

【摘要】：为解决目前生物絮团技术碳源成本过高以及由于木薯渣处理困难造成的环境问题,本文探究了酶解木薯渣作为生物絮团碳源的可行性。首先本文优化了酶解木薯渣的工艺流程,然后将最佳反应条件下得到的酶解产物与原木薯渣、蔗糖作为三种不同的碳源添加进南美白对虾养殖水体中,最后通过水质分析,判断蔗糖、木薯渣和酶解木薯渣三种碳源对水质影响的区别,并利用高通量测序技术对生物絮团和对虾肠道中的微生物群落结构进行解析。本研究对高效利用木薯渣,解决其造成的环境问题具有重要意义,也为解释生物絮团的作用机理提供了理论参考。主要结果归纳如下:(1)确定了纤维素酶、糖化酶和α-淀粉酶单独水解木薯渣的最佳pH、反应温度、酶添加量、固液比和最佳反应时间。(2)确定了当纤维素酶、糖化酶和α-淀粉酶添加量分别为8000 U/g木薯渣、4000 U/g木薯渣和640 U/g木薯渣,反应时间分别为48 h、10 h和40 h时,三种酶复合作用的最佳效果比单一酶种最佳的作用效果提高了97.92%,同时该结果明显高于理论上三种酶解效果之和。(3)取预处理过的木薯渣,分别调节固液比为1/15、1/10、1/5,并在不同条件下依次添加七种生物酶,最终得到的还原糖的浓度分别34.75 mg/mL、50.55 mg/mL、92.32mg/mL和,相较于未经处理的木薯渣,还原糖提取率提高了 20倍。(4)在周期为30天的养殖实验中,分别将蔗糖、木薯渣、酶解木薯渣添加到对虾养殖桶中,水质分析表明,蔗糖组的氨氮浓度(0.16 mg/L)和亚硝态氮浓度(0.13 mg/L)相较于木薯渣组分别降低了 23.8%和27.8%,酶解木薯渣组的氨氮浓度(0.19 mg/L)和亚硝态氮浓度(0.16 m/L)分别降低了 9.5%和12.5%,TSS(总固体悬浮物浓度)和BFV(生物絮团体积浓度)水平最高的组为酶解木薯渣组。蔗糖在控制氨氮、亚硝态氮两种污染指标方面效果最好,其次是酶解木薯渣,但是在生物絮团的形成方面,酶解木薯渣的处理效果最好。(5)高通量测序结果表明,生物絮团中的微生物多样性远高于对虾肠道,BFT3(碳源为酶解木薯渣的生物絮团)中异养细菌的相对丰度分别比BFT1(碳源为蔗糖的生物絮团)和BFT2(碳源为木薯渣的生物絮团)高了 20.70%和和1.19%,同时其益生菌的相对丰度比BFT1和BFT2高了 11.47%和61.60%,来自于BFT3水环境培养的对虾肠道样品中,致病菌所占的比例低于其他两组,说明了酶解木薯渣的添加提高了益生菌和异养细菌并且抑制了致病菌来降低对虾的疾病风险。
[Abstract]:In order to solve the environmental problems caused by the high cost of carbon source and the difficulty of cassava residue treatment, the feasibility of enzymatic cassava residue as a carbon source of biological floc was explored. Firstly, the technological process of enzymatic cassava residue was optimized. The enzymatic hydrolysis products and cassava dregs, sucrose as three different carbon sources were added to the culture water of Penaeus vannamei under the best reaction conditions. Finally, the sucrose was judged by the analysis of water quality. The effects of cassava residue and enzymatic cassava residue on water quality were studied. The microbial community structure in biological flocs and shrimp intestines was analyzed by high-throughput sequencing. It is of great significance to solve the environmental problems caused by it, and also provides a theoretical reference for explaining the action mechanism of biological flocs. The main results are summarized as follows: 1) Cellulase is determined. The optimum pH, reaction temperature, enzyme addition, solid-liquid ratio and optimum reaction time of cassava residue hydrolyzed separately by Glucoamylase and 伪 -amylase were determined. The dosages of Glucoamylase and 伪 -amylase were 8 000 U / g cassava dregs and 640 U / g cassava dregs respectively, and the reaction time was 48 h / 10 h and 40 h respectively. The optimum effect of the three enzymes was 97.922.The result was significantly higher than that of cassava dregs pretreated with the sum of the three enzymatic hydrolysis effects in theory, and the optimum effect of the three enzymes was higher than that of the single enzyme, and the result was significantly higher than that of the pre-treated cassava dregs. The ratio of solid to liquid was adjusted to 1 / 15 / 1 / 10 / 1 / 5, and seven kinds of biological enzymes were added under different conditions, and the final concentration of reducing sugar was 34.75 mg / mL, 50.55 mg / mL and 92.32 mg / mL, respectively, compared with the untreated cassava residue. The extraction rate of reducing sugar was increased by 20 times. 4) in the culture experiment with a period of 30 days, sucrose, cassava residue and cassava residue were added to the shrimp culture barrel respectively. The water quality was analyzed. The ammonia concentration of sucrose group (0.16 mg / L) and nitrite concentration (0.13 mg / L) decreased by 23.8% and 27.8 respectively compared with cassava dregs, the ammonia concentration of enzymatic cassava dregs was 0.19 mg / L and nitrite concentration was 0.16 mg / L and 9.5% and 12.5 mg / L, respectively. The highest concentration of floatation) and BFV (volume concentration of biological flocs) were obtained from cassava dregs by enzymatic hydrolysis. Sucrose was used to control ammonia nitrogen. The effect of nitrite nitrogen on two pollution indexes was the best, followed by enzymatic cassava residue, but in the formation of biological flocs, the treatment effect of enzymatic cassava residue was the best. The microbial diversity in the biological flocs is much higher than that in the shrimp intestinal tract BFT3 (where the carbon source is enzymatic cassava residue) and the relative abundance of heterotrophic bacteria is higher than that of BFT1 (carbon source is sucrose biological flocs) and BFT2 (carbon source is cassava residue). At the same time, the relative abundance of probiotics was 11.47% and 61.60 higher than that of BFT1 and BFT2. The proportion of pathogenic bacteria was lower than that of the other two groups, which indicated that the addition of cassava residue could increase probiotics and heterotrophic bacteria and inhibit pathogenic bacteria to reduce the risk of shrimp disease.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X714

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