电沉积制备MnO2催化剂及其在微生物燃料电池中的应用

通过电沉积的方法获得了一种具有均匀孔隙结构的海绵状二氧化锰催化剂,结合扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)等手段表征了所制备材料的表面形貌、结构及元素构成和赋存价态,采用线性伏安扫描(LSV)法对电沉积材料的电化学性能进行分析,考察其催化氧还原反应的活性,最后以合成的材料为阴极催化剂,构建微生物燃料电池系统,考察其在微生物燃料电池中的应用效果。结果表明,以电沉积二氧化锰为阴极催化剂的微生物燃料电池最大功率密度为975.6 mW/m~2,是以商业二氧化锰为阴极催化剂的电池的1.7倍;这表明作为一种经济、高效、环境友好的阴极氧还原催化剂,电沉积法制备的二氧化锰为实现阴极催化剂的低成本制备以及微生物燃料电池放大化推进提供了新的研究途径。     

Biotic Cathode of Graphite Fibre Brush for Improved Application in Microbial Fuel Cells

The biocathode in a microbial fuel cell (MFC) system is a promising and a cheap alternative method to improve cathode reaction performance. This study aims to identify the effect of the electrode combination between non-chemical modified stainless steel (SS) and graphite fibre brush (GFB) for constructing bio-electrodes in an MFC. In this study, the MFC had two chambers, separated by a cation exchange membrane, and underwent a total of four different treatments with different electrode arrangements (anodeǁcathode)—SSǁSS (control), GFBǁSS, GFBǁGFB and SSǁGFB. Both electrodes were heat-treated to improve surface oxidation. On the 20th day of the operation, the GFBǁGFB arrangement generated the highest power density, up to 3.03 W/m³ (177 A/m³), followed by the SSǁGFB (0.0106 W/m³, 0.412 A/m³), the GFBǁSS (0.0283 W/m³, 17.1 A/m³), and the SSǁSS arrangements (0.0069 W/m⁻³, 1.64 A/m³). The GFBǁGFB had the lowest internal resistance (0.2 kΩ), corresponding to the highest power output. The other electrode arrangements, SSǁGFB, GFBǁSS, and SSǁSS, showed very high internal resistance (82 kΩ, 2.1 kΩ and 18 kΩ, respectively) due to the low proton and electron movement activity in the MFC systems. The results show that GFB materials can be used as anode and cathode in a fully biotic MFC system.     

微生物降解塑料的研究进展

聚羟基脂肪酸酯(PHAs)是许多原核微生物在不平衡生长条件下合成的细胞内能量和碳源储藏性物质,作为完全可生物降解的热塑性聚酯而倍受关注。它除了具有与化学合成高分子相似的性质外,还具有比重大、光学活性好、透氧性低、抗紫外线辐射、生物可降解性、生物组织相溶性、压电性和抗凝血性等特点,因而在电子、光学、农业、生物医学、食品包装等领域具有广阔的应用前景。本文主要综述了近几年来国内外对PHAs微生物合成的研究进展,同时对PHAs的应用前景进行了展望。     

The sources of thermal energy exchange accompanying microbial anabolism

Calculations are made of the thermal energy exchanges accompanying the anabolism of Saccharomyces cerevisiae of four substrates using the equations and . Contrary to a previous postulate cited in the Discussion, the free-energy changes accompanying anabolism are not zero, but can be either positive or negative. However, their magnitude with either sign is small compared to that of catabolism of the same substrates, so that even with free energy changes that are negative it is unlikely anabolism can be considered a spontaneous process.     

不动杆菌静息细胞催化拆分外消旋环戊酮醇乙酸酯反应条件的优化

 考察了反应条件对不动杆菌Acinetobactersp．YQ231催化外消旋环戊酮醇乙酸酯对映选择性水解的反应速度和对映选择性的影响．确定的最佳酶反应条件为pH8．0，温度50℃．不同乳化剂对对映选择性的影响不同，以壬基酚聚氧乙烯醚的效果最好，当其加入量为15g／L时，反应的对映选择性最高．产物环戊酮醇对酶活性有显著的抑制作用．细胞中的酯酶优先水解（R）－环戊酮醇乙酸酯，生成（R）－环戊酮醇，在底物浓度为250mmol／L时，对映体比率（E值）可达50．     

Phylogenetic characterization of a mixed microbial community capable of degrading carbon tetrachloride

Two bacterial communities (NO92 and GBS) capable of degrading carbon tetrachloride (CT) were enriched from in-house CT-contaminated water. These communities are able to degrade CT in the presence of toluene. To characterize the community structure and diversity, one enrichment (NO92) was subjected to 16S ribosomal RNA (rRNA) gene-based molecular analysis. The 16S rRNA genes were amplified from the bulk genomic community DNA and cloned into plasmid vectors. Unique 16S rRNA gene clones, i.e., phylotypes, were detected by four tetrameric restriction enzymes. Together, 123 16S rRNA gene clones were obtained; thirty-one showed different restriction fragment length polymorphism (RFLP) patterns. About 73% of the clones belong to two dominant RFLP patterns. Phylogenetic analysis based on the partial 16S rRNA gene sequences of 10 major phylotypes showed that all the phylotypes that were sequenced were affiliated with the high G+C Gram-positive bacteria. Whereas seven of the phylotypes (∼80% of the clones) were closely related to Rhodococcus, the other three (∼5% of the clones) were related to Curtobacterium. These results suggest that this CT-degrading community is diverse but is predominated by closely related bacterial groups.     

甘油在微生物代谢合成及生物催化中的应用

生物柴油是一种可再生能源,因其可替代石油来源的柴油而日益受到重视。随着生物柴油工业的蓬勃发展,其制备过程中的主要副产物甘油出现明显的产能过剩。作为一种廉价的清洁资源,甘油的深度开发和利用既是发展生物柴油工业的关键,也符合绿色化学的发展要求。近年来,甘油不仅作为重要的起始原料用于一些高附加值化学品的制备,而且因其独特的理化性质和易降解、生物相容性好等特性,在生物催化和绿色溶剂领域的应用研究日趋活跃。本文主要综述了甘油在工业微生物发酵、生物合成和绿色溶剂领域的研究进展,并就其应用中存在的一些问题,如甘油原料品质和微生物利用效率等进行分析,同时展望了甘油在生物催化领域的应用前景。     

NiY分子筛的合成及在微生物电解池阴极的析氢性能研究

在Na₂O-Al₂O₃-SiO₂-H₂O体系中添加硝酸镍,采用导向剂法合成了NiY分子筛。利用XRD、SEM、TEM、N₂吸附-脱附等手段对合成的NiY分子筛进行了表征。结果表明,随着镍添加量的增加,结晶度和zeta电位呈先增大后减小的趋势。当Si/Ni （mol ratio）大于5时,硝酸镍对分子筛的形成具有促进作用,当Si/Ni （mol ratio）小于5时,则具有抑制作用。晶粒粒径为1.5-3 μm,形貌为凹槽结构的六方或四方柱型,且具有微孔-介孔多级孔道结构特征。通过循环伏安曲线和极化曲线测试,在Si/Ni （mol ratio）=5时,样品的氧化还原性能最强,过电势最小,电催化活性最高。在12 h内,每4 mg的Si/Ni （mol ratio）=5样品,产气总量为10.1 mL,氢气纯度达81.69%,与Pt电极相比其氢气产量提高了28%。NiY分子筛表现出良好的析氢催化活性,有望取代Pt成为MEC新型阴极材料。     

基质辅助激光解析/电离飞行时间质谱(MALDI-TOF MS)在微生物鉴定中的应用*

基质辅助激光解析/电离飞行时间质谱(MALDI-TOF MS)是一种新型软电离生物质谱,具有检测速度快、操作简便、结果准确等优点,目前已成为可靠的微生物快速鉴定技术。就工作流程而言,与常规生化方法相比,MALDI-TOF MS可以将微生物鉴定的时间缩短为一天甚至更短。对于具有抗生素耐药性的微生物,使用MALDI-TOF MS鉴定也有很好的准确性。在病毒鉴定中,MALDI-TOF MS也可以发挥作用,已有报道将MALDI-TOF MS和机器学习(ML)分析方法结合来检测鼻拭子中SARS-CoV-2。此外,MALDI-TOF MS还可用于细菌的无光谱库鉴定。目前,MALDI-TOF MS正通过与其他技术(例如傅里叶红外光谱FTIR)相结合进一步扩大微生物鉴定范围。     

Natural Dietary Compound Xanthohumol Regulates the Gut Microbiota and Its Metabolic Profile in a Mouse Model of Alzheimer’s Disease

Discovering new and effective drugs for the treatment of Alzheimer’s disease (AD) is a major clinical challenge. This study focuses on chemical modulation of the gut microbiome in an established murine AD model. We used the 16S rDNA sequencing technique to investigate the effect of xanthohumol (Xn) on the diversity of intestinal microflora in 2-month- and 6-month-old APP/PS1 mice, respectively. APP/PS1 and wild-type mice were treated by gavage with corn oil with or without Xn every other day for 90 days. Prior to and following treatment, animals were tested for spatial learning, cognitive and memory function. We found Xn reduced cognitive dysfunction in APP/PS1 mice and significantly regulated the composition and abundance of gut microbiota both in prevention experiments (with younger mice) and therapeutic experiments (with older mice). Differential microflora Gammaproteobacteria were significantly enriched in APP/PS1 mice treated with Xn. Nodosilineaceae and Rikenellaceae may be the specific microflora modulated by Xn. The penicillin and cephalosporin biosynthesis pathway and the atrazine degradation pathway may be the principal modulation pathways. Taken together, oral treatment with Xn may have a neuroprotective role by regulating the composition of intestinal microflora, a result that contributes to the scientific basis for a novel prophylactic and therapeutic approach to AD.