Inhibitory effects and biotransformation of acrylic acid in computer-controlled pH-Stat CSTRs

Abstract

In this study, the inhibitory effects and anaerobic biotransformation of acrylic acid in computer‐controlled pH‐stat completely stirred tank reactors (CSTRs) with two different cultures, namely unacclimated and acrylate‐acclimated acetate‐enriched Methanosarcina and homogenized (crushed) granular cultures, were investigated. The microbial acclimation, influent concentration, and loading rate of acrylic acid were studied in the experiments. The experimental results revealed that methanogenic cultures at a concentration of 3200 ± 80 mg/L as volatile suspended solids (VSS) could be acclimated to acrylic acid up to a loading rate of 220 mg/L per day (0.068 g acrylic acid/g VSS per day) in the presence of a constant acetate concentration of 2000 ± 200 mg/L as the primary substrate after 300 days of acclimation. The same cultures (680 ± 80 mg/L as VSS), after 80 days of acclimation to acrylic acid as the sole carbon source, transformed acrylic acid up to the loading rate of about 200 mg/L per day (0.29 g acrylic acid/g VSS per day) almost completely (>99%) to acetic and propionic acid, but could not effectively metabolize these intermediate products. Acrylate‐acclimated homogenized granular cultures (6900 ± 80 mg/L as VSS) effectively metabolized 2200 mg/L per day (0.32 g acrylic acid/g VSS per day) of acrylic acid, as the sole carbon source, after 50 days of severe inhibition. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 62: 200–207, 1999.

Volatile Fatty Acid Production from Organic Fraction of Municipal Solid Waste Through Anaerobic Acidogenic Digestion

“…The reactors (R1, R2, R3, and R4) were operated as pH-stat CSTRs (Demirer and Speece, 1999). The pH-stat CSTR system consisted of a magnetically stirred glass reactor of 1-L effective volume with a headspace of 500 mL (Fig.…”

Biological wastewater treatment for removal of polymeric resins in UASB reactor: influence of oxygen

“…Attempts for removal of these compounds have been made in anaerobic conditions, but results have been poor (Dangcong & Xingwen 1994;Araya et al 1999Araya et al , 2000. It is said that the main limiting step is the inhibition of the methanogenic activity produced by the concentration of polymeric resins compounds (PRC) and the accumulation of intermediates (Stuckey et al 1980;Grbić -Galić et al 1990;Demirer & Speece 1999). Most of the studies under anaerobic conditions have shown that the problems in the treatment of the wastewater are the compounds conforming the resins.…”

Biodegradación anaerobia de compuestos petroquímicos

“…La utilización de sustratos primarios en la degradación de ácido acrílico está poco documentada, en algunos estudios se han utilizado altas concentraciones de acetato (2000 mg•L -1 ), no obstante se requieren largos periodos de aclimatación (300 días) para degradar una carga orgánica volumétrica de 220 mg•L -1 •d -1 de este ácido (Demirer y Speece, 1999).…”

“…Aunque los periodos de recuperación en este estudio parecen prolongados, se ha reportado que en un cultivo enriquecido con Methanosarcina utilizando acetato (2000 mg•L -1 ) como sustrato primario, 900 mg•L -1 de ácido acrílico causaron inhibición sobre las bacterias utilizadoras de acetato y propionato, requiriendo un periodo de 44 días para recuperar la actividad sobre estos sustratos en reactores de tanque agitado. Mientras que para un cultivo homogenizado y en el que predominaban bacterias acetogénicas y metanogénicas después de 50 días de inhibición el ácido acrílico fue consumido como único sustrato (Demirer y Speece, 1999).…”

“…•d -1 . Este resultado mostró que el lodo adaptado a la mezcla de compuestos, fue capaz de degradar completamente el ácido acrílico, en un tiempo de adaptación menor a los reportados como único sustrato o con acetato como cosustrato (Demirer y Speece, 1999).…”