Development of a chemically defined medium for Planctopirus limnophila to increase biomass production

BackgroundPlanctomycetes is a phylum of biofilm-forming bacteria with numerous biosynthetic gene clusters, offering a promising source of new bioactive secondary metabolites. However, the current generation of chemically defined media achieves only low biomass yields, hindering research on these species. We therefore developed a chemically defined medium for the model organism Planctopirus limnophila to increase biomass production.ResultsWe found that P. limnophila grows best with a 10 mM sodium phosphate buffer. The replacement of complex nitrogen sources with defined amino acid solutions did not inhibit growth. Screening for vitamin requirements revealed that only cyanocobalamin (B12) is needed for growth. We used response surface methodology to optimize the medium, resulting in concentrations of 10 g/L glucose, 34 mL/L Hutner’s basal salts, 23.18 mM KNO₃, 2.318 mM NH₄Cl and 0.02 mg/L cyanocobalamin. The analysis of amino acid consumption allowed us to develop a customized amino acid solution lacking six of the amino acids present in Aminoplasmal 10%. Fed-batch cultivation in a bioreactor using the optimized medium achieved a final ΔOD₆₀₀ of 46.8 ± 0.5 after 108 h, corresponding to a cell dry weight of 13.6 ± 0.7 g/L.ConclusionsThe optimized chemically defined medium allowed us to produce larger amounts of biomass more quickly than reported in earlier studies. Further research should focus on triggering P. limnophila biofilm formation to activate the gene clusters responsible for secondary metabolism.How to cite: Kruppa OC, Gerlach D, Fan R, et al. Development of a chemically defined medium for Planctopirus limnophila to increase biomass production. Electron J Biotechnol 2021;54. https://doi.org/10.1016/j.ejbt.2021.09.002.     

栽培式教育的理论基础

当下的教育惟分数论依然十分严重,对人的培养反而成了对学生的压制。为了改变这种现状,我们提出了栽培式教育的理念。栽培式教育的理论基础有人本主义、建构主义、多元智能理论和素质教育等。     

Ethics and economics: A comment on Narvaez‘s “Revitalizing human virtue by restoring organic morality”

This paper comments on Darcia Narvaez's Kohlberg Memorial Lecture, published in this issue, with respect to her contrasting ethics and economics, or morality and market. My basic claim is that ethics and economics, properly understood, are just two sides of the same coin. One main point is that all morality solves cooperation problems and includes positive and negative sanctions to uphold it. The second claim is that competition in market economies is, in principle, ethically justified, and where it creates a problem, it is not just an ethical problem, but by the same token an economic one with which economists are concerned.     

让德育之花盛开在英语教学中

英语教学不仅要注重知识的传授,而且要注重德育教育,只有把二者有机地结合起来,文道统一,才能达到教书育人的目的。     

大学自由教育的生成逻辑与实践路径探析

自由教育时常被冠以自由主义教育的标签,但其精神实质与当前我国倡导的“学生发展核心素养”教育异曲同工,应该得以澄清。自由教育在国家层面上与社会主义本质及核心价值观的全面发展一致,在社会层面上与科教强国的创新驱动一致,在个人层面上与人才培养的人文关怀一致。因此,高校应该把自由教育与人才培养相结合、把自由教育与创新教育相结合、把自由教育与个人成长相结合。     

培养高技能人才与营造学习型组织氛围

高技能人才是指既有比较高的理论素养与知识水平,又具有比较强的操作能力与实践经验的复合人才。由于种种原因,我国目前高技能人才尚严重缺乏,营造学习型组织和高技能人才培养的良好氛围是解决这一问题的有效途径。     

浅论孔子的道德教育思想

孔子道德教育的基本内涵及其整个思想理论定库中的核心内容是：人际和谐，遵循“仁爱”的原则；安顾治国，“为政以德”，坚持德教为先的原则；“有教无类”，坚持德育为首的原则；进行道德修养，坚持螳，思，行统一的原则。搞清，学懂，借鉴并坚持实践这些原则，对加强我国的物质文明和精神文明建设，对保证国家的长治久安都将起积极的推进作用。     

试析高职学生品德培养途径的心理学依据

目前我们一些从事学生品德教育的人员大多局限于“知其然不知其所以然”的感性认识阶段。本文试从心理学角度，就高职学生必备的品德心理结构形成过程及其变化规律，阐明若干教育途径和措施的心理学依据，使品德培养工作真正建立在科学的基础上，做到言之有据、有理。     

正确培养大学生的数学思维品质

以发展个性思维为目的，探讨了培养学生思维的精度、速度、新度、深度、广度等五个方面的思维品质。     

试论高等教育创新的基本原则

目前 ,我国高等学校进一步扩大招生 ,为适应社会发展的需要各高校在课程设置、教学教法以及后勤社会化等方面都有所创新 ,进行了一系列的改革。我国高等教育的创新是高层次的创新 ,是国家创新体系的支柱和基础 ,它的创新可遵循一些基本原则 ,其中最主要的是个性培养原则、整体培养原则、动态化原则、实践性原则等