Phosphate loading alters schwertmannite transformation rates and pathways during microbial reduction

2019 ◽  
Vol 657 ◽  
pp. 770-780 ◽  
Author(s):  
Valerie A. Schoepfer ◽  
Edward D. Burton ◽  
Scott G. Johnston ◽  
Peter Kraal
Keyword(s):  
Microbial Reduction ◽  
Transformation Rates ◽  
Phosphate Loading

The Effect of Mixtures of Xenobiotics and Primary Electron Donor on the Anaerobic Biotransformation of High Concentrations of Chlorinated Aliphatics

1992 ◽  
Vol 26 (1-2) ◽  
pp. 117-126 ◽  
Author(s):  
J. B. Hughes ◽  
G. F. Parkin
Keyword(s):  
Electron Donor ◽  
Mixed Effects ◽  
Primary Electron ◽  
Primary Electron Donor ◽  
Loading Rates ◽  
Chlorinated Aliphatics ◽  
Anaerobic Biotransformation ◽  
Transformation Rates ◽  
High Concentrations ◽  
Effect Of Feeding

Results are presented from experiments addressing the anaerobic biotransfoimation of high concentrations of three chlorinated aliphatics, dichloromethane (DCM), chloroform (CF), and 1,1,1-trichloroethane (TCA), when fed alone and in mixtures. Experiments were conducted to address the effect of feeding mixtures of these compounds on the transformation rates of individual components in the mixture, and to assess the effect of acetate loading rates on the extent of transformation of the chlorinated aliphatics. Feeding mixtures of chlorinated aliphatics caused decreased transformation of TCA, increased the transformation of DCM, and had mixed effects on CF transformation. The systems fed higher acetate loading rates demonstrated an increased ability to transform the chlorinated aliphatics.

scholarly journals The Effect of Gaseous Ozone Generated by Surface Dielectric Barrier Discharge on the Decay and Quality of Stored Onion Bulbs

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1058
Author(s):  
Junghyun Lim ◽  
Jong-Seok Song ◽  
Sangheum Eom ◽  
Jung Woo Yoon ◽  
Sang-Hye Ji ◽  
...  
Keyword(s):  
Untreated Control ◽  
Color Change ◽  
Microbial Reduction ◽  
Ozone Exposure ◽  
Onion Bulbs ◽  
Gaseous Ozone ◽  
Surface Dielectric Barrier Discharge ◽  
Postharvest Loss ◽  
High Voltage Discharge

An effective and eco-friendly technology is needed to prevent postharvest loss of onion bulbs during cold storage. This study investigated the effect of gaseous ozone on the decay and quality of onion bulbs during storage at 2 °C and 70% relative humidity for two months. Gaseous ozone was adjusted to a concentration of 1.27 ± 0.024 ppm in the storage room by generating a high voltage discharge in air. After two months of storage, gaseous ozone significantly reduced the counts of aerobic bacteria (e.g., Rahnella aquatilis) and fungi (e.g., yeast and mold) in the onion bulbs by 4 log (CFU g−1) and 0.92 log (CFU g−1) compared with those of an untreated control, respectively. The microbial reduction by gaseous ozone resulted in a lower rotten rate of the onion bulbs, which was less than 20.0% compared with that of the untreated control. Moreover, the ozone exposure extended the storage life of the onion bulbs by delaying its color change and softening during storage. Our results suggest that gaseous ozone can control the decay of onion bulbs safely during storage.

Impact of sanitizer solutions on microbial reduction and quality of fresh-cut pennywort (Centella asiatica) leaves

2021 ◽  
Author(s):  
Siti Zaharah Rosli ◽  
Mohd Adzahan Noranizan ◽  
Son Radu ◽  
Roselina Karim ◽  
Noraniza Mohd Adzahan ◽  
...  
Keyword(s):  
Centella Asiatica ◽  
Microbial Reduction ◽  
Fresh Cut

scholarly journals Insight to Microbial Fe(III) Reduction Mediated by Redox-Active Humic Acids with Varied Redox Potentials

2021 ◽  
Vol 18 (13) ◽  
pp. 6807
Author(s):  
Jingtao Duan ◽  
Zhiyuan Xu ◽  
Zhen Yang ◽  
Jie Jiang
Keyword(s):  
Molecular Weight ◽  
Electron Transfer ◽  
Humic Acids ◽  
Weight Fraction ◽  
Electrochemical Analysis ◽  
Microbial Reduction ◽  
Redox Potentials ◽  
Groundwater Environment ◽  
Redox Active ◽  
Different Molecular Weight

Redox-active humic acids (HA) are ubiquitous in terrestrial and aquatic systems and are involved in numerous electron transfer reactions affecting biogeochemical processes and fates of pollutants in soil environments. Redox-active contaminants are trapped in soil micropores (<2 nm) that have limited access to microbes and HA. Therefore, the contaminants whose molecular structure and properties are not damaged accumulate in the soil micropores and become potential pollution sources. Electron transfer capacities (ETC) of HA reflecting redox activities of low molecular weight fraction (LMWF, <2.5) HA can be detected by an electrochemical method, which is related to redox potentials (Eh) in soil and aquatic environments. Nevertheless, electron accepting capacities (EAC) and electron donating capacities (EDC) of these LMWF HA at different Eh are still unknown. EDC and EAC of different molecular weight HA at different Eh were analyzed using electrochemical methods. EAC of LMWF at −0.59 V was 12 times higher than that at −0.49 V, while EAC increased to 2.6 times when the Eh decreased from −0.59 V to −0.69 V. Afterward, LMWF can act as a shuttle to stimulate microbial Fe(III) reduction processes in microbial reduction experiments. Additionally, EAC by electrochemical analysis at a range of −0.49–−0.59 V was comparable to total calculated ETC of different molecular weight fractions of HA by microbial reduction. Therefore, it is indicated that redox-active functional groups that can be reduced at Eh range of −0.49–−0.59 are available to microbial reduction. This finding contributes to a novel perspective in the protection and remediation of the groundwater environment in the biogeochemistry process.

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