TY - JOUR

T1 - Role of bacterivorous organisms on fungal-based systems for natural tannin degradation

AU - Sigona, Cristiana

AU - Bardi, Alessandra

AU - Modeo, Letizia

AU - Mori, Gualtiero

AU - Potekhin, Alexey

AU - Verni, Franco

AU - Munz, Giulio

AU - Petroni, Giulio

N1 - Publisher Copyright: © 2020

PY - 2020/4

Y1 - 2020/4

N2 - Tannery wastewater presents high concentrations of organic load and pollutant recalcitrant molecules (e.g. tannins), which reduce the efficiency of biological treatment processes. Recent studies showed that several fungal species and strains are effective in the degradation of tannins. However, high bacterial load can negatively affect fungal growth, reducing system stability and degradation performances. The aim of the present study was to evaluate the effects of the introduction of bacterivorous grazers (ciliates and/or rotifers) in batch scale experiments using fungi to remove Tara tannin, i.e. to check the potential synergistic effect between fungi and bacterivorous grazers in the degradation of recalcitrant compounds. In this context, the ciliated grazers Paramecium calkinsi, Tetrahymena sp., Pseudovorticella sp., and the rotifer Lecane inermis, preliminary selected according to their ability to grow in a solution prepared with Tara tannin, were separately tested. Activated sludge, including a complex mixture of native grazers, was used as experimental control. The following parameters were monitored: bacterial load, number of grazers/mL and Soluble Chemical Oxygen Demand (SCOD). Colony Forming Unit (CFU)/grazers ratio was also calculated. Particular attention was paid to: i) bacterial load reduction and ii) enhancement of recalcitrant compounds degradation, and we observed that in all experimental conditions where grazers occurred bacterial load was significantly reduced and the system achieved a higher SCOD removal in a shorter time. Our findings provide useful insights for the stabilization of fungal-based systems in non-sterile conditions.

AB - Tannery wastewater presents high concentrations of organic load and pollutant recalcitrant molecules (e.g. tannins), which reduce the efficiency of biological treatment processes. Recent studies showed that several fungal species and strains are effective in the degradation of tannins. However, high bacterial load can negatively affect fungal growth, reducing system stability and degradation performances. The aim of the present study was to evaluate the effects of the introduction of bacterivorous grazers (ciliates and/or rotifers) in batch scale experiments using fungi to remove Tara tannin, i.e. to check the potential synergistic effect between fungi and bacterivorous grazers in the degradation of recalcitrant compounds. In this context, the ciliated grazers Paramecium calkinsi, Tetrahymena sp., Pseudovorticella sp., and the rotifer Lecane inermis, preliminary selected according to their ability to grow in a solution prepared with Tara tannin, were separately tested. Activated sludge, including a complex mixture of native grazers, was used as experimental control. The following parameters were monitored: bacterial load, number of grazers/mL and Soluble Chemical Oxygen Demand (SCOD). Colony Forming Unit (CFU)/grazers ratio was also calculated. Particular attention was paid to: i) bacterial load reduction and ii) enhancement of recalcitrant compounds degradation, and we observed that in all experimental conditions where grazers occurred bacterial load was significantly reduced and the system achieved a higher SCOD removal in a shorter time. Our findings provide useful insights for the stabilization of fungal-based systems in non-sterile conditions.

KW - Bacterivorous organisms

KW - Batch tests

KW - Biotechnology

KW - Fungal degradation

KW - Grazing

KW - Microbiology

KW - Microorganism

KW - Mycology

KW - Protozoa

KW - Tannins removal

KW - BIODEGRADATION

KW - PERFORMANCE

KW - COMMUNITIES

KW - CILIATED PROTOZOA

KW - WASTEWATERS

KW - MICROFAUNA

KW - ROTIFERS

KW - TEXTILE

KW - SLUDGE

KW - WATER

UR - http://www.scopus.com/inward/record.url?scp=85082551452&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/1b97a3d1-4d1e-31e1-82e2-71c493600438/

U2 - 10.1016/j.heliyon.2020.e03604

DO - 10.1016/j.heliyon.2020.e03604

M3 - Article

AN - SCOPUS:85082551452

VL - 6

JO - Heliyon

JF - Heliyon

SN - 2405-8440

IS - 4

M1 - e03604

ER -