Development of a Rapid Ferricyanide-Mediated Assay for Biochemical Oxygen Demand Using a Mixed Microbial Consortium

Abstract

Ferricyanide-mediated (FM) microbial reactions were used for the rapid determination of the biochemical oxygen demand (BOD) of a range of synthetic and real wastewater samples. Four single-species microbial seeds and a synthetically prepared microbial consortium were compared. In all cases, the microbial consortium exhibited a greater extent and rate of biodegradation compared to the individual microbial seeds. Markedly improved correlation to the standard BOD5 method was also noted for the microbial consortium (compared to the single-species seeds). A linear dynamic range up to 200 mg BOD5 L(-1) was observed, which is considerably greater than the linear range of the standard BOD5 assay and most other rapid BOD assays reported. In addition, biodegradation efficiencies comparable to the 5-day BOD5 assay (and much greater than other rapid BOD assays) were observed in 3 h. A highly significant correlation (R = 0.935, p = 0.000, n = 30) between the FM-BOD method and the standard BOD5 method was found for a wide diversity of real wastewater samples. The results indicate that the FM-BOD assay is a promising, rapid, alternative to the standard 5-day BOD5 assay.

MICREDOX®—development of a ferricyanide-mediated rapid biochemical oxygen demand method using an immobilised Proteus vulgaris biocomponent

“…Second, unlike oxygen, the reduced form of the mediator has an initial background concentration of zero, thereby increasing the accuracy when quantifying the amount of oxidised mediator converted to its reduced form. In recent studies, we demonstrated that the ferricyanide-mediated microbial oxidation of organic substrates by Eschericha coli in a 1-h MICREDOX ® incubation was equivalent to that achieved in the traditional BOD 5 test (60.5%) (Pasco et al, 2000;Morris et al, 2001;Catterall et al, 2003). A second application, again demonstrated with E. coli, confirmed the utility of this method for rapidly quantifying the effect of toxic substances on microbial catabolism .…”

“…In all reported cases, the decrease in dissolved oxygen forms the basis of the analytical signal. One consequence of oxygen limitation for microbial BOD sensors is the amount of organic material biodegraded in a short-time assay is small, representing only a very small fraction of the total biodegradable organic content Catterall et al, 2003). Mini-wastewater treatment plants, such as RODTOX ® , BIOX ® , BIOMONITOR ® and RACOD ® are designed to replicate the operation of a wastewater treatment plant, rather than the methodology of the BOD test.…”

Biodesulphurization of thiophene as a sulphur model compound in crude oils by Pseudomonas aeruginosa supported on polyethylene

“…Pseudomonas species are able to grow with cyanide as the sole nitrogen source and several enzyme activities of these bacterial strains were significantly higher than those observed with other nitrogen sources [34]. Also the bacterial cells exhibited a greater extent and rate of biodegradation in the presence of ferricyanide as the terminal electron acceptor compared to the individual cells [35].The purpose of this study is to investigate biodesulphurization ability of P. aeruginosa supported on polyethylene in the presence of potassium hexacyanoferrate(III) in thiophene biodegradation as an aromatic sulphur model compound of crude oil.…”

Biochemical Oxygen Demand (BOD)

“…Ferricyanide (FC) acts as an efficient mediator for shuttling electrons between the redox centers of reduced bacterial enzymes and the electrode surface. 6 In the presence of FC as a mediator, electrons derived from the oxidation of organic substrates in aerobic catabolism are transferred to the FC ion which is reduced from ferricyanide to ferrocyanide, 7 as shown in Eq. (2.1).…”