caa a22 4500 605502625 CHVBK 20210128100606.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s00253-015-6891-8 doi (NATIONALLICENCE)springer-10.1007/s00253-015-6891-8 Directed evolution to produce sludge communities with improved oxygen uptake abilities [Elektronische Daten] [Stephanie Kunkel, Krishna Pagilla, Benjamin Stark] Two activated sludge cultures, seeded with activated sludge from the same source, were cultivated for 370days in synthetic wastewater. Both cultures were transferred weekly to fresh medium; one culture was operated at high dissolved oxygen (DO) (near saturation) and the other at low DO (0.25mgO2/L). There were significant changes in the abundances of bacterial species and phyla present in each culture throughout the 370-day operational period. In the low DO culture, over time, there was a continuously increasing proportion of cells of species known to encode truncated hemoglobins (Hbs). These are the types of Hbs which may enhance delivery of oxygen to the respiratory chain, to enhance ATP production, especially under low aeration conditions. The levels of heme b, the heme found in Vitreoscilla hemoglobin, increased in parallel to the increase in Hb-encoding species, to much higher levels in the low DO culture than in the high DO culture. Specific oxygen uptake rates increased by 3% for the high DO culture near the end of the 370-day period, while those for the low DO culture increased steadily to a level 28% higher than that of the starting culture. Thus, imposition of low DO conditions may, due to selection for Hb-expressing species, be useful in developing bacterial communities with enhanced ability to function efficiently in aerobic wastewater treatment, especially under low aeration conditions. Springer-Verlag Berlin Heidelberg, 2015 Aerobic treatment nationallicence Bacterial hemoglobins nationallicence Directed evolution nationallicence Low oxygen conditions nationallicence Wastewater nationallicence Kunkel Stephanie Department of Biology, Illinois Institute of Technology, 60616, Chicago, IL, USA aut Pagilla Krishna Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, 60616, Chicago, IL, USA aut Stark Benjamin Department of Biology, Illinois Institute of Technology, 60616, Chicago, IL, USA aut Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/24(2015-12-01), 10725-10734 0175-7598 99:24<10725 2015 99 253 https://doi.org/10.1007/s00253-015-6891-8 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00253-015-6891-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kunkel Stephanie Department of Biology, Illinois Institute of Technology, 60616, Chicago, IL, USA aut NATIONALLICENCE 700 1- Pagilla Krishna Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, 60616, Chicago, IL, USA aut NATIONALLICENCE 700 1- Stark Benjamin Department of Biology, Illinois Institute of Technology, 60616, Chicago, IL, USA aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/24(2015-12-01), 10725-10734 0175-7598 99:24<10725 2015 99 253