Physicochemical,textural and volatile characteristics of fermented milk co-cultured with Streptococcus thermophilus,Bifidobacterium animalis or Lactobacillus plantarum

Fermented milks were prepared with various culture combinations of Lactobacillus plantarum or Bifidobacterium animalis with Streptococcus thermophilus, and the impact of microbes combinations on acidification, proteolysis, lipolysis, texture, volatiles and sensory quality of fermented milk was investigated during 21-day storage at 4 °C. The results showed that products from the co-cultures displayed higher titratable acidity, more peptides, higher proteolytic activity and lipolysis capacity compared with that from the pure strains of S. thermophilus. When L. plantarum and B. animalis combined in a ratio of 2:1 with S. thermophilus, the products maintained relatively more viable cell counts of the 3 strains, strong proteolysis ability and lipolysis capacity during the storage. Milk fermented by co-cultures of the 3 strains exhibited higher cohesiveness, more volatiles and better sensory quality compared with these fermented by S. thermophilus only or in co-cultures with either B. animalis or L. plantarum based on principal component analysis.     

One‐Step Construction of N,P‐Codoped Porous Carbon Sheets/CoP Hybrids with Enhanced Lithium and Potassium Storage

Despite the desirable advancement in synthesizing transition‐metal phosphides (TMPs)‐based hybrid structures, most methods depend on foreign‐template‐based multistep procedures for tailoring the specific structure. Herein, a self‐template and recrystallization–self‐assembly strategy for the one‐step synthesis of core–shell‐like cobalt phosphide (CoP) nanoparticles embedded into nitrogen and phosphorus codoped porous carbon sheets (CoP?NPPCS), is first proposed. Relying on the unusual coordination ability of melamine with metal ions and the cooperative hydrogen bonding of melamine and phytic acid to form a 2D network, a self‐synthesized single precursor can be attained. Importantly, this approach can be easily expanded to synthesize other TMPs?NPPCS. Due to the unique compositional and structural characteristics, these CoP?NPPCSs manifest outstanding electrochemical performances as anode materials for both lithium‐ and potassium‐ion batteries. The unusual hybrid architecture, the high specific surface area, and porous features make the CoP?NPPCS attractive for other potential applications, such as supercapacitors and electrocatalysis.     

原位固氮剂在污泥堆肥过程中保氮机制

高温好氧堆肥技术虽然可有效处理有机固体废物，但常常会释放大量的氨气和造成氮素损失。本文以硫酸镁、磷酸二氢钾、硫酸镁+磷酸二氢钾（分别记为MgSO₄、KP和KPM处理组）为原位固氮剂，污泥和木屑为原料，进行高温好氧堆肥试验，研究以上原位固氮剂对污泥堆肥过程中的氨气挥发和氮素损失的影响。结果表明，硫酸镁（MgSO₄）对物料pH有显著的降低效应，添加硫酸镁使堆体高温期pH降低至8.17，低于硫酸镁+磷酸二氢钾（KPM）组（8.55）和对照（CK）组（8.90）。与CK相比，MgSO₄和KPM的NH₃累积释放量分别降低了34%和28%，反而KP组增加了35%。对比不同条件下XRD图谱可知，MgSO₄的固氮效应并不是由于MgNH₄PO₄·6H₂O的生成，而是由于其对pH的降低效应造成的。堆肥结束后，除了KP组，各处理条件下的种子发芽率值（germination index，GI）均不会对后续使用带来不利影响。     

化学沉淀-吸附法处理电镀废水的研究

采用化学沉淀-吸附法处理电镀废水。首先,采用沉淀剂MgSO4・7H2O和NazHPCX・12H2O对电镀废水进行化学沉淀处理。在优化条件下,氨氮的质量浓度由1600 mg/L降低至80 mg/L以下,磷的质量浓度为75.82 mg/Lo然后,采用吸附法对电镀废水做进一步处理。最终电镀废水中氨氮和磷的残余质量浓度均达到《电镀污染物排放标准》(GB 219002008)中规定的要求。     

中国铅锌矿能源资源基地开发利用现状研究

我国铅锌矿产资源丰富，生产能力、消费量、出口量居世界前列，是我国的优势矿种。以10个铅锌矿能源资源基地为研究对象，对基地分布、矿山数量、产能结构、开发利用指标、矿业固废循环利用指标等进行了分析研究。研究表明，2018年，我国铅锌矿大型资源基地的矿业集中度和铅锌矿的综合利用率均高于全国平均水平。     

Silver(I)-Ion-Mediated Cytosine-Containing Base Pairs: Metal Ion Specificity for Duplex Stabilization and Susceptibility toward DNA Polymerases

Spectroscopic characterization of Ag^I-ion-mediated C-Ag^I-A and C-Ag^I-T base pairs found in primer extension reactions catalyzed by DNA polymerases was conducted. UV melting experiments revealed that C-A and C-T mismatched base pairs in oligodeoxynucleotide duplexes are specifically stabilized by Ag^I ions in 1:1 stoichiometry in the same manner as a C-C mismatched base pair. Although the stability of the mismatched base pairs in the absence of Ag^I ions is in the order C-A≈C-T>C-C, the stabilizing effect of Ag^I ions follows the order C-C>C-A≈C-T. However, the comparative susceptibility of dNTPs to Ag^I-mediated enzymatic incorporation into the site opposite templating C is dATP>dTTP≫dCTP, as reported. The net charge, as well as the size and/or shape complementarity of the metal-mediated base pairs, or the stabilities of mismatched base pairs in the absence of metal ions, would be more important than the stability of the metallo-base pairs in the replicating reaction catalyzed by DNA polymerases.     

Effect of Cultivation Parameters on Fermentation and Hydrogen Production in the Phylum Thermotogae

The phylum Thermotogae is composed of a single class (Thermotogae), 4 orders (Thermotogales, Kosmotogales, Petrotogales, Mesoaciditogales), 5 families (Thermatogaceae, Fervidobacteriaceae, Kosmotogaceae, Petrotogaceae, Mesoaciditogaceae), and 13 genera. They have been isolated from extremely hot environments whose characteristics are reflected in the metabolic and phenotypic properties of the Thermotogae species. The metabolic versatility of Thermotogae members leads to a pool of high value-added products with application potentials in many industry fields. The low risk of contamination associated with their extreme culture conditions has made most species of the phylum attractive candidates in biotechnological processes. Almost all members of the phylum, especially those in the order Thermotogales, can produce bio-hydrogen from a variety of simple and complex sugars with yields close to the theoretical Thauer limit of 4 mol H₂/mol consumed glucose. Acetate, lactate, and L-alanine are the major organic end products. Thermotagae fermentation processes are influenced by various factors, such as hydrogen partial pressure, agitation, gas sparging, culture/headspace ratio, inoculum, pH, temperature, nitrogen sources, sulfur sources, inorganic compounds, metal ions, etc. Optimization of these parameters will help to fully unleash the biotechnological potentials of Thermotogae and promote their applications in industry. This article gives an overview of how these operational parameters could impact Thermotogae fermentation in terms of sugar consumption, hydrogen yields, and organic acids production.