Hydrogen and methane production from household solid waste in the two-stage fermentation process

A two-stage process combined hydrogen and methane production from household solid waste was demonstrated working successfully. The yield of 43 mL H(2)/g volatile solid (VS) added was generated in the first hydrogen production stage and the methane production in the second stage was 500 mL CH(4)/g VS added. This figure was 21% higher than the methane yield from the one-stage process, which was run as control. Sparging of the hydrogen reactor with methane gas resulted in doubling of the hydrogen production. pH was observed as a key factor affecting fermentation pathway in hydrogen production stage. The optimum pH range for hydrogen production in this system was in the range from 5 to 5.5. The short hydraulic retention time (2 days) applied in the first stage was enough to separate acidogenesis from methanogenesis. No additional control for preventing methanogenesis in the first stage was necessary. Furthermore, this study also provided direct evidence in the dynamic fermentation process that, hydrogen production increase was reflected by acetate to butyrate ratio increase in liquid phase.     

合成气生物发酵法制乙醇的研究进展

采用合成气生物发酵法制乙醇具有反应条件温和、产物选择性高、原料来源广泛、低碳可持续发展等优势,是一种具有前景的可再生能源新型生产工艺。文章综述了合成气发酵法制乙醇的微生物种类及对应的适宜操作条件,分析了合成气发酵法制乙醇的Wood-Ljungdahl代谢途径;总结了合成气的广泛来源;分析讨论了过程工艺参数如合成气组成及压力、pH、温度、培养基组分、气液传质对合成气发酵的影响;指出合成气发酵法制乙醇面临的底物传质性能差、乙醇收率低等关键问题,比较了典型反应器在传质方面的差异,归纳了传质强化方法;总结了合成气发酵法制乙醇的工业化进展, 并提出了未来的发展方向。     

Design and implementation of an ultrasonic sensor for rapid monitoring of industrial malolactic fermentation of wines

Ultrasound is an emerging technology that can be applied to monitor food processes. However, ultrasonic techniques are usually limited to research activities within a laboratory environment and they are not extensively used in industrial processes. The aim of this paper is to describe a novel ultrasonic sensor designed to monitor physical–chemical changes that occur in wines stored in industrial tanks. Essentially, the sensor consists of an ultrasonic transducer in contact with a buffer rod, mounted inside a stainless steel tube section. This structure allows the ultrasonic sensor to be directly installed in stainless steel tanks of an industrial plant. The operating principle of this design is based on the measurement of ultrasonic velocity of propagation. To test its proper operation, the sensor has been used to measure changes of concentration in aqueous samples and to monitor the progress of a malolactic fermentation of red wines in various commercial wineries. Results show the feasibility of using this sensor for monitoring malolactic fermentations in red wines placed in industrial tanks.     

酢辣椒中微生物成分变化的研究

采用多菌种混合发酵法制酢辣椒,利用多波长扫描法测定所得酢辣椒中微生物的数量.通过与传统发酵法作比较,探索两种酢辣椒中微生物数量的变化关系,为酢辣椒的大规模工业自动化生产提供理论参考.     

ORP调控对葡萄糖和果糖混合底物丁醇发酵的影响

采用氧化还原电位(oxidoreduction potential,ORP)调控以模拟菊芋块茎酸解液(葡萄糖和果糖混合糖)为底物进行的丙酮丁醇发酵过程,能够有效控制"酸崩溃"现象的发生。已通过实验确定最佳调控策略为控制整个发酵过程的ORP不低于-460mV。本研究在最佳调控策略下,发酵终点丁醇浓度从3.39g/L提高到11.65g/L,残糖浓度从30.82g/L降低到1.38g/L。对比ORP调控组和对照组发现,ORP调控能够改变发酵过程中细胞内还原力水平,能量状态和代谢流向,因此ORP调控能有效防止"酸崩溃"现象发生,调节菌体生长和溶剂产量。ORP调控策略应用于以葡萄糖和果糖混合糖为底物的丁醇发酵具有操作可行性,是一种简便而有效的工艺优化手段。     

膜生物反应器 CCCF 过程中酵母细胞生长特性研究

渗透汽化膜生物反应器CCCF过程乙醇发酵中酵母细胞的生长表现出五个不同的阶段,即：快速生长期、乙醇抑制期、二次生长期、平衡期和衰亡期。采用摇瓶实验对发酵副产物（主要为有机酸和甘油）的抑制行为进行检测,结果表明随着副产物浓度的增加,抑制作用越来越强,细胞生长表现出较长的迟滞期和较低的细胞浓度。当副产物浓度达到膜生物反应器中发酵后期的浓度时,细胞的比生长速率和得率仅分别为0．061和0．024。     

响应面法优化从丝状真菌中制取壳聚糖的研究

以黑根霉、黑曲霉作为原料,研究了制备壳聚糖的方法。通过液体发酵获得黑根霉、黑曲霉的菌丝体,经干燥研磨后,比较稀酸稀碱热处理及微波法处理制备壳聚糖的提取效果及产率,并对微波法进行响应面的优化实验。结果表明：微波法较稀酸稀碱法提取效果好,产率高。优化结果：微波火力为480 W,消解时间为15 min,碱浓度为20％。     

汽爆甘蔗渣转化乙醇的实验研究

研究了甘蔗渣的汽爆条件,并利用高效液相色谱（HPLC）对甘蔗渣汽爆产物进行了分析。在相同汽爆蒸汽压力下,随着汽爆保压时间的延长,降解产生的对后续酶解和发酵有害的物质甲酸、乙酸和糠醛等也随之增加。研究了汽爆甘蔗渣的酶解和发酵性能,在实验室小试的基础上,进一步利用50 L发酵罐进行放大的酶解和发酵实验,在酶解液固形物浓度27.09%（ω）条件下,48 h发酵液乙醇浓度6.17%（φ）,显示汽爆甘蔗渣能够较好地被转化用于生产乙醇。     

热带假丝酵母发酵生产长链二元酸的节能减排措施

热带假丝酵母发酵生产长链二元酸在菌体、空气、烃类(油)和水的四相发酵体系中完成,发酵过程需氧量大、放热量高,提纯过程多处存在升温、降温过程,生产成本高。采用"倒推法"分析了装置公用工程消耗的主要影响因素,通过节能改造,余热、废汽与废水回收,正常生产每年可节省生产成本390余万元。     

餐厨垃圾厌氧发酵过程的影响因素硏究

餐厨垃圾虽是废物,但经过厌氧发酵,可以产生发酵产物和沼气,厌氧发酵可以将有机垃圾变废为宝,同时获得清洁能源,减少碳排放,取得良好的社会和经济效益。在本文中,对餐厨垃圾厌氧沼气发酵系统进行了全面的研究,通过探讨食物垃圾物理组成,研究影响餐厨垃圾厌氧发酵的各种因素,通过研究找出餐厨垃圾厌氧发酵的最佳反应条件,进行餐厨垃圾厌氧发酵实验室测试得出实验结论。