NaCl对餐厨垃圾厌氧发酵产VFA浓度及组分的影响

通过间歇实验研究了最适反应条件(pH值为6.0、温度为35℃)下NaCl含量对餐厨垃圾厌氧发酵产挥发性脂肪酸(VFA)的影响.考察了NaCl含量为0.0,3.0,6.0,9.0,12.0g/L下的有机酸浓度及组成情况.结果表明,NaCl对厌氧发酵液中VFA浓度影响显著,随NaCl含量提高VFA浓度呈下降趋势,当NaCl含量达到12.0g/L时,VFA浓度在第114h达到最大值4.14g/L,仅为未添加NaCl条件下的10.1%.发酵液中各组分变化经历丁酸积累、乙酸积累与乙酸消耗3个阶段,NaCl对厌氧发酵类型影响不显著,各批次发酵均为丁酸型发酵,仅当NaCl含量超过6.0g/L时丁酸积累阶段时间延长.     

类芽孢杆菌产絮凝多糖发酵条件优化及成分分析

为提高微生物絮凝多糖的产量,应用响应面方法对一株高效产絮菌株A9〔类芽孢杆菌(Paenibacillus sp.)〕发酵产絮凝多糖的影响因素进行分析. 结果表明:①根据P-B(Plackett-Burman)法确定,影响A9产絮凝多糖的显著因子为装瓶量、ρ(MgSO₄·7H₂O)和ρ(可溶性淀粉);②通过Box-Behnken试验设计及响应面分析,确定了优化的培养基组成与培养条件,在ρ(可溶性淀粉)为17g/L,ρ(酵母膏)为3.0g/L,ρ(K₂HPO₄)为6g/L,ρ(MgSO₄·7H₂O)为0.2g/L,ρ(NaCl)为0.10g/L,装瓶量为51mL(250mL锥形瓶),pH为8的优化条件下,絮凝多糖实际产量为2.49g/L,与理论预测值(2.50g/L)接近;③利用红外光谱法检测A9产絮凝多糖的特征基团分别为—OH、—COO-、—C—O—C—和—NHCOCH₃等极性基团;④结合A9对不同碳源利用的单因素试验结果,推测A9产絮凝多糖的主要成分分别为含有α-吡喃型糖苷键的甘露糖和葡萄糖、酸性多糖和乙酰氨基多糖等.      

辣椒秸秆不同部位化学组分及厌氧发酵产沼气潜力

以辣椒苏椒16号为试验材料,调查统计了辣椒生物量和产废系数,并在实验室条件下,研究了辣椒秸秆不同部位理化特性及厌氧发酵产沼气潜力,及各部位对辣椒整株的影响.结果表明：辣椒秸秆生物量高达21t/hm²,产废系数为0.36.辣椒秸秆各部位间理化特性及产沼气潜力具有显著性差异（P<0.05）,产沼气潜力大小顺序为：叶（185.2mL/gVS）>茎（104.2mL/gVS）>根（68.9mL/gVS）.各部位对辣椒整株的影响主要表现在纤维素和碳水化合物的相对含量对其产沼气的影响.且根据经验分子式推测的理论产沼气量,对辣椒秸秆厌氧发酵产沼气转化率进行了评估,各部位转化率均较低,其原因有待进一步研究.     

Sludge fermentation liquid addition attained advanced nitrogen removal in low C/N ratio municipal wastewater through short-cut nitrification-denitrification and partial anammox

• Sludge fermentation liquid addition resulted in a high NAR of 97.4%. • Extra NH₄⁺-N from SFL was removed by anammox in anoxic phase. • Nitrogen removal efficiency of 92.51% was achieved in municipal wastewater. • The novel system could efficiently treat low COD/N municipal wastewater. Biological nitrogen removal of wastewater with low COD/N ratio could be enhanced by the addition of wasted sludge fermentation liquid (SFL), but the performance is usually limited by the introducing ammonium. In this study, the process of using SFL was successfully improved by involving anammox process. Real municipal wastewater with a low C/N ratio of 2.8–3.4 was treated in a sequencing batch reactor (SBR). The SBR was operated under anaerobic-aerobic-anoxic (AOA) mode and excess SFL was added into the anoxic phase. Stable short-cut nitrification was achieved after 46d and then anammox sludge was inoculated. In the stable period, effluent total inorganic nitrogen (TIN) was less than 4.3 mg/L with removal efficiency of 92.3%. Further analysis suggests that anammox bacteria, mainly affiliated with Candidatus_Kuenenia, successfully reduced the external ammonia from the SFL and contributed approximately 28%–43% to TIN removal. Overall, this study suggests anammox could be combined with SFL addition, resulting in a stable enhanced nitrogen biological removal.     

Treatment of biologically treated effluents from baker's yeast industry by membrane and ozone technologies

This paper presents pilot‐scale membrane treatment results performed on biologically treated effluents from fermentation industry and ozone oxidation on concentrates from the same membrane treatment system. The results obtained from the ultrafiltration (UF) and/or the reverse osmosis (RO) systems indicate that membrane treatment are very effective for COD, Color, NH₃‐N and conductivity removal. Ozone oxidation of the membrane concentrates was tested to increase biodegradability of the wastes. The initial ratios of Biochemical oxygen demand (BOD₅) to Chemical oxygen demand (COD) were increased significantly by applying chemicaloxidation with O₃ and O₃ + H₂O₂.     

Zn2+及Fe3+对嗜淀粉乳杆菌开放式发酵产乳酸的影响

研究了在餐厨垃圾中接种嗜淀粉乳杆菌进行开放式乳酸发酵(即发酵原料不灭菌)的可行性,探讨了添加Fe3+、Zn2+的发酵体系中相关酶活与代谢产物的关系.结果表明,开放式发酵体系的乳酸产量高于非开放式发酵体系.加Fe3+体系的乳酸脱氢酶活性较高,导致乳酸产量增加(最高达29.5g/L),比未添加微量元素的对照体系增加了24.2%;而加Zn2+体系的乙醇脱氢酶(ADH)活性较高,导致副产物乙醇产量的增加,从而使乳酸产量低于对照体系;添加不同微量元素时嗜淀粉乳杆菌对底物中淀粉的利用率由高到低的顺序为:加Fe3+体系(65.7%) > 对照体系 (38.5%)>Zn2+体系(28.1%).此外,在嗜淀粉乳酸菌的发酵体系中,蔗糖和麦芽糖比乳糖容易降解成葡萄糖,果糖,最终被乳酸菌利用.     

利用浓缩污泥对污水中污染物的连续回收试验

为了回收污水中的有机物、氮和磷以便资源化,在工艺流程为好氧活化-好氧吸附-厌氧释放连续流处理系统中,研究了浓缩污泥对模拟生活污水中污染物的吸附及污泥中污染物的厌氧释放,确定了活化浓缩污泥所需时间,揭示了吸附段HRT对污泥吸附效果的影响及厌氧释放段pH对污泥中污染物释出的影响. 结果表明,污水厂浓缩污泥好氧活化120 min以上即可提高其对污染物的吸附/吸收能力. 控制吸附段HRT为25～50 min和污泥负荷〔N_s,为投配COD_Cr量(kg)/污泥量(kg·d)〕为3～5 kg/(kg·d),系统运行良好. 活化污泥对COD_Cr,NH₄+-N和PO₄3--P的最大去除率分别为86.78%,64.78%和75.5%. 在连续厌氧释放段,pH对各污染物释放的影响不尽相同,在pH为11.0,SRT为3 d的条件下,COD_Cr,NH₄+-N和PO₄3--P分别被浓缩了3.6,1.3和8.4倍.      

初期通气和震荡培养提高高浓度乙醇发酵的乙醇浓度和产率

研究了氧气和震荡条件对酿酒酵母高浓度乙醇发酵的影响.结果表明,震荡是提高发酵液乙醇浓度和产率的最重要因素.与静止培养相比,在不通气情况下震荡培养使乙醇浓度提高了69%(从75.8 g L-1提高到128.1 g L-1),在通气条件下乙醇浓度提高了68.7%(从85.2 g L-1提高到to 143.8 g L-1).在最优条件下,两次补料,经54 h发酵,发酵液中乙醇浓度达到143.8 g L-1,乙醇产率与理论产率的比值为0.471 g/g(即92.20%).经分析,通气和震荡条件提高了发酵液中酿酒酵母的生物量和细胞活力.图5表1参12     

混合菌种在发酵法生物产氢中的协同作用

为探讨产氢发酵细菌混合培养时菌种间的协同作用,本研究在间歇试验条件下,分别考察以葡萄糖和复杂有机物(淀粉、牛肉膏、聚乙二醇乙二酸酯和胰蛋白胨)为底物时,5株HPB(B49、H1、LM12、LM11和B51)混合培养,高效HPB(B49)与3株非产氢发酵细菌(L10、拟3-2和芽孢1)分别混合培养,以及B49与活性污泥混合培养对产氢能力的影响.试验结果表明,混合菌种间协同作用发挥是有条件的.当利用葡萄糖发酵产氢时,菌种间对共同底物的竞争使其协同作用无法发挥,从而制约了高效产氢细菌(HPB)的产氢能力;而利用复杂有机物发酵产氯时,菌种间的协同作用得以发挥,并促进了高效HPB产氢能力的提高.同时提出,针对不同底物可以采用不同的培养方式.