Comprehensive evaluation of starter culture impact on the bioreactor performance and microbial kinetics


Demirkaya E., Ciftcioglu B., Özyıldız G. , Zengin Balcı G. E. , Pala-Ozkok I. , Çokgör E. , ...More

BIOCHEMICAL ENGINEERING JOURNAL, vol.177, 2022 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 177
  • Publication Date: 2022
  • Doi Number: 10.1016/j.bej.2021.108233
  • Title of Journal : BIOCHEMICAL ENGINEERING JOURNAL
  • Keywords: Activated sludge, Filamentous organisms, Inoculum, Modelling, Respirometry, ACTIVATED-SLUDGE, WASTE-WATER, FILAMENTOUS BULKING, MICROTHRIX-PARVICELLA, NUTRIENT REMOVAL, FEEDING PATTERN, CARBON-SOURCES, BATCH TESTS, BACTERIA, GROWTH

Abstract

The present study investigated the disregarded impact of microbial community composition, diversity and abundance of the starter biomass on lab-scale bioreactor performance, steady-state long time operation, biodegradation outcome and microbial kinetics. Standard lab-scale experiments are usually initiated with inoculum taken from wastewater treatment plants (WWTPs) without considering microbial community composition. Two identical sequencing batch bioreactors (SBR-1, SBR-2) were operated with inocula obtained from two domestic WWTPs to assess the role of inoculum composition on reactor performance and treatment efficacy. Filamentous microorganisms were dominated in SBR-1 (SVI: 265 mL/g), whereas their supremacy was diminished in SBR-2 (SVI: 160 mL/g). Next generation sequencing analyses verified high abundance of Candidatus Microthrix (14%) and Kouleothrix spp. (3%) in SBR-1. Although Chloroflexi C10-SB1A metagenome accounted for 16% of WWTP-2 community, SBR-2 was operated at steady-state for longer period without deterioration. Statistical indicators based on molecular studies showed that WWTP-2 has higher diversity than WWTP-1. Higher biodiversity in WWTP-2 community supported the stable process performance. Modelling studies denoted an increase in half saturation coefficients (K-s) in filamentous microorganisms dominated reactor. The results of this study provide insight on how the filamentous organisms typically found in WWTPs become a fundamental constituent during the bioreactor operation.