Article
Biotechnology & Applied Microbiology
Sergey M. Abramov, Daniel Straub, Julian Tejada, Lars Grimm, Franziska Schaedler, Aleksandr Bulaev, Harald Thorwarth, Ricardo Amils, Andreas Kappler, Sara Kleindienst
Summary: In the mining-impacted Rio Tinto, Spain, Fe-cycling microorganisms play a crucial role in the transport of heavy metals into the Atlantic Ocean. This study investigates how the hydrogeochemical gradients along the Rio Tinto shape the composition of Fe-cycling microbial communities and their impact on heavy metal mobility. The findings suggest that the water column and sediment in the estuary harbor diverse microbial communities that mediate the iron cycle, and tidal water influences the composition and activity of the Fe-cycling taxa, which in turn affects the transport of heavy metals.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
(2022)
Review
Biology
Eric Alexander Runge, Muammar Mansor, Andreas Kappler, Jan-Peter Duda
Summary: Deep-sea hydrothermal systems are important for the emergence of life, but the distribution and diversity of microbial communities in ancient systems are still unclear. Understanding the formation and preservation of microbial biosignatures in these systems is challenging and requires multidisciplinary studies.
Article
Biotechnology & Applied Microbiology
Jianrong Huang, Adrian Mellage, Julian Pavon Garcia, David Gloeckler, Susanne Mahler, Martin Elsner, Natalia Jakus, Muammar Mansor, Hongchen Jiang, Andreas Kappler
Summary: Autotrophic nitrate-reducing Fe(II)-oxidizing microorganisms play a crucial role in carbon, iron, and nitrogen cycles. The study showed that the distribution of electrons from Fe(II) oxidation to either CO2 fixation or nitrate reduction deviated from the theoretical value. N2O was the main denitrification product. Furthermore, the Fe/N ratios influenced the distribution of electrons and the degree of cell-mineral interactions.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
(2023)
Article
Engineering, Environmental
Guoqiang Zhao, Mengxi Tan, Binbin Wu, Xiaoshan Zheng, Ruoxuan Xiong, Baoliang Chen, Andreas Kappler, Chiheng Chu
Summary: Tidal-induced redox oscillations can activate thermodynamically stable iron minerals into a metastable phase for enhanced ROS production.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Geochemistry & Geophysics
Qian Zheng, Shuxin Tu, Yiwen Chen, Hongjun Zhang, William Hartley, Bangjiao Ye, Lu Ren, Juan Xiong, Wenfeng Tan, Andreas Kappler, Jingtao Hou
Summary: This study investigates the adsorption behavior of As(III) and As(V) on ferrihydrite. The results show that ferrihydrite has a higher affinity for As(III) and contains abundant micropores that contribute to the immobilization of As(III).
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Multidisciplinary Sciences
Jannik Martens, Carsten W. Mueller, Prachi Joshi, Christoph Rosinger, Markus Maisch, Andreas Kappler, Michael Bonkowski, Georg Schwamborn, Lutz Schirrmeister, Janet Rethemeyer
Summary: In Siberian permafrost sediments deposited during the Pleistocene, the presence of reactive iron leads to the mineral-bound organic carbon, which reduces microbial CO2 production after thawing. Rapid thaw of ice-rich Pleistocene-age permafrost can expose a large pool of organic matter to microbial degradation and greenhouse gas emissions, but protective physico-chemical mechanisms may restrict microbial accessibility and reduce decomposition, influenced by changing environmental conditions during sediment deposition. Study of different organic matter fractions in Siberian permafrost deposited during colder and warmer periods reveals that carbon preservation in mineral-associated organic matter is enhanced by reactive iron minerals, while warmer and wetter conditions reduce organic matter stabilization and increase CO2 production. The stability and bioavailability of Pleistocene-age permafrost carbon are important for predicting future climate-carbon feedback.
NATURE COMMUNICATIONS
(2023)
Article
Engineering, Environmental
Yuge Bai, Tianran Sun, Muammar Mansor, Prachi Joshi, Yiling Zhuang, Stefan B. Haderlein, Stefan Fischer, Kurt O. Konhauser, Daniel S. Alessi, Andreas Kappler
Summary: In this study, the roles of dissolved organic matter (DOM) and organo-mineral associations (OMAs) in electron transfer were investigated during microbial Fe-(III)-mineral reduction. Only when both DOM and OMAs were present, significant electron transfer occurred. The proportion of DOM and OMAs showed a positive correlation with the extent of Fe-(III) mineral reduction, but the variation in DOM proportion had a stronger effect on the reduction compared to OMAs. These findings provide new insights into how organic carbon facilitates iron transformation and the associated biogeochemical cycling of nutrients and contaminants in forest soil systems.
ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS
(2023)
Article
Engineering, Environmental
Dandan Chen, Kuan Cheng, Tongxu Liu, Guojun Chen, Andreas Kappler, Xiaomin Li, Raymond Jianxiong Zeng, Yang Yang, Fujun Yue, Shiwen Hu, Fang Cao, Fangbai Li
Summary: This study demonstrates that dual N-O isotopes and kinetic modeling can be used to distinguish biological and chemical processes during microbially mediated NRFO. The main nitrate reductase in Acidovorax sp. strain BoFeN1 was found to be membrane-bound dissimilatory nitrate reductase (Nar). N-O isotopes can be used to differentiate between chemical and biological reactions, and chemodenitrification plays a more important role than biological reactions during the coupled process.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Juan Liu, Yongjin Xiang, Yiwen Chen, Hongjun Zhang, Bangjiao Ye, Lu Ren, Wenfeng Tan, Andreas Kappler, Jingtao Hou
Summary: This study synthesized hematite samples with tunable oxygen vacancy defect (OVD) concentrations and investigated their effects on arsenate adsorption. The results revealed that oxygen vacancy was the primary defect type on the hematite surface. Quantitative relationships between OVD concentration and enhanced arsenate adsorption were established. NH3-DRIFT analysis and DFT calculations demonstrated the beneficial role of OVDs in improving adsorption strength and promoting arsenate immobilization.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Zhao-Feng Yuan, Yujie Zhou, Zheng Chen, Tong Zhang, Andreas Kappler, Williamson Gustave, Xianjin Tang, Jianming Xu
Summary: A new sustainable method using man-made aerenchymatous tissues (MAT) to increase soil redox potential (Eh) and reduce arsenic accumulation in rice paddies has been proposed and verified.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Bobo Xing, Nigel J. D. Graham, Binghao Zhao, Xian Li, Youneng Tang, Andreas Kappler, Hailiang Dong, Mari Winkler, Wenzheng Yu
Summary: Biomineralization occurring in the bacterial periplasmic space enhances electron transfer. Denitrification-driven Fe(II) oxidation plays a crucial role in connecting iron and nitrogen cycling in the environment. This study investigated the pathways and effects of iron entering the periplasmic space of the denitrifier Pseudomonas sp. JM-7, providing insights into the microbial metabolism and electron transfer in relation to iron presence.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Review
Microbiology
Laurent Philippot, Claire Chenu, Andreas Kappler, Matthias C. Rillig, Noah Fierer
Summary: Considerable progress has been made in recent years in determining the soil properties that influence the structure of the soil microbiome. However, the effects of microorganisms on their soil habitat have received less attention. Microorganisms not only contribute to nutrient cycling and organic matter transformations, but also alter the soil habitat through various mechanisms. Understanding the interactions between microorganisms and soil properties can have significant ecological implications.
NATURE REVIEWS MICROBIOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Timm Bayer, Ran Wei, Andreas Kappler, James M. Byrne
Summary: The adsorption capacity and overall efficiency of mixed-valent magnetite nanoparticles (MNPs) for heavy metal pollutants are influenced by their redox state and surface charge, which are affected by microbial redox cycling of iron (Fe) in magnetite and changes in pH. Microbial modification of MNPs has an important impact on the adsorption of Cu2+ and Cd2+, and a change in stoichiometry of the MNPs can have a greater influence than a change of pH.
ACS EARTH AND SPACE CHEMISTRY
(2023)
Article
Environmental Sciences
Lu Lu, Saskia Rughoeft, Daniel Straub, Samantha B. B. Joye, Andreas Kappler, Sara Kleindienst
Summary: This study provides evidence that the biosurfactant rhamnolipid is more efficient than the chemical dispersants Corexit 9500 and Slickgone NS in stimulating oil biodegradation in natural seawater. The impacts of biosurfactants on microbial community composition and oil biodegradation activities were examined using time-course microcosm experiments. The results showed high hydrocarbon oxidation rates and microbial activities in the rhamnolipid-amended oil microcosms. The findings suggest that biosurfactants have great promise for future marine oil spill responses.
Article
Environmental Sciences
Anh Van Le, E. Marie Muehe, Sharon Bone, Soren Drabesch, Stefan Fischer, Andreas Kappler
Summary: Household sand filters (SFs) are commonly used to remove groundwater contaminants in low-income regions. This study investigated the removal of Fe, As, and Mn under unsaturated and saturated conditions. The results showed effective removal of Fe and As under both conditions, while leaching of Mn occurred under saturated conditions. The presence of Mn(IV) oxides during unsaturated conditions played a significant role in the oxidation and removal of Fe and As.
