Mineral deficiency appears to pose a more critical problem in the anaerobic treatment process than in the aerobic treatment process. Furthermore, the methane fermentation step of anaerobic treatment appears to be the stage most sensitive to mineral deficiency. Commonly the mineral deficiency is a trace metal, and, since the fermentation step is the terminal stage in the treatment process, a build‐up of these reactants (mainly acetate, propionate, butyrate and hydrogen) can adversely affect the overall process. A review of the literature follows concerning the mineral requirements of methane fermentation in order to facilitate a proper understanding of the anaerobic process, especially in its application to treatment of industrial waste waters that are prone to be deficient in certain minerals. Types of limiting nutrients are considered with specific attention given to nitrogen, sulfur, phosphorus and the trace metals, and the physiological role and intracellular concentration of minerals is discussed. An ...

Mineral requirements for methane fermentation

The effect of the addition of trace elements on the conversion of a mixture of volatile fatty acids (Acetate, Propionate, Butyrate, in a ratio 3:1:1) by anaerobic granular sludge was investigated. Two Upflow Anaerobic Sludge Bed reactors (pH 7, 30°C) were operated for 140 days at an organic loading rate ranging from 2 g COD l−1 d−1 up to 10 g COD 1−1 d−1 and a hydraulic retention time of 12 hours. One reactor (Rl) was supplied with a trace metal cocktail in the basal medium, whereas trace metals were omitted from the influent of the second reactor (R2). As a result, the trace metal concentration in the granules from R2 steadily decreased at a rate of 48 μg metal g−1 TS d−1 down to 35% of their initial value. In contrast, trace metals accumulated in granules present in Rl. At the end of the experiment, the COD removal efficiencies were 99 and 77% for, respectively, the control (R1) and deprived (R2) reactors. This difference was due to lack of propionate conversion by sludge from R2. No difference...

Effects of trace element addition on volatile fatty acid conversions in anaerobic granular sludge reactors

Trace organic nutrient and metal requirements for the growth of Methanococcoides methylutens strain TMA-10 were determined in defined medium that contained trimethylamine as the substrate. Biotin was the only organic supplement required in place of yeast extract, Trypticase or a mixture of 8 B-vitamins. Fe an Ni were required for growth and low concentrations of Fe2+ (<5 μM) and Ni2+ (<0.25 μM) provided limited growth. In the absence of added Co the growth rate was reduced by 94% and growth was limited at concentrations below 0.1 μM. Stimulation of growth by Se, Mo, B, Al, Zn, Mn or Cu could not be demonstrated.

Trace metal and vitamin requirements of Methanococcoides methylutens grown with trimethylamine

Abstract Cells of the archaebacterium Methanosarcina barkeri were grown strictly anaerobic in defined media. 57Fe-Mössbauer Spectroscopy of methanol grown cells oxidized in the presence of air demonstrated only the state of Fe3+ whereas active cells under reducing conditions offered spectra of two additional iron sites in the Fe2+ state. Furthermore the 57Fe hyperfine interaction data at different temperatures gave evidence that cells cultivated with methanol or acetate as substrate contained ferredoxin like compounds.

P. Scherer

Papers

State of Iron in the Archaebacterium Methanosarcina barkeri Grown on Different Carbon Sources as Studied by Mössbauer Spectroscopy