Large-scale anaerobic degradation of betaine

Abstract

Betaine, also known as N,N,N-trimethyl glycine, is a soluble nitrogenous compound present at signi®cant concentrations in sugar-beet molasses. Molasses is used as substrate in a wide range of industrial fermentations, for example, alcohol, acid and yeast cell production. Betaine is not consumed to any signi®cant extent during these fermentations and appears to largely pass through the subsequent processing stages, becoming an important constituent of the wastewater produced by these industries. The present study con®rmed that betaine is present in large amounts in sugar-beet molasses (up to 6% w/w) and in the ef¯uent of processes using sugar-beet molasses as substrate (up to 4.5 g dm ). Betaine appeared to be almost completely degraded in the two full-scale anaerobic treatment plants sampled. This was con®rmed by anaerobic activity tests performed with both acclimated and unacclimated anaerobic sludge. The results obtained suggest the possible involvement of a multistep degradation process, with the likelihood of a nitrogen-containing intermediate. Finally, although not totally discountable, betaine degradation does not appear to be coupled to sulfate reduction during treatment of high-sulfate wastewaters.

Efficiency of aerobic biodegradation of beet molasses vinasse under non-controlled pH: conditions for betaine removal / Efektywność tlenowej biodegradacji buraczanego wywaru melasowego przy nieregulowanym pH podłoża: określenie warunków usunięcia betainy

“…Its composition is characterized in Table 1. Since betaine is not detected by the dichromatic analysis of COD (Thalasso et al 1999), the parameter COD sum , defi ned as the sum of the vinasse COD and the theoretical COD of betaine (2.097 g O 2 /g betaine), was introduced as one of the parameters describing the pollution load of the stillage examined.…”

“…In our preliminary studies into biodegradation of vinasse carried out with the same bacterial culture, the reduction in COD was 85.37% and 76.48% at controlled pH and uncontrolled pH, respectively. In both the instances the microorganisms failed to remove betaine (the main pollutant of beet molasses vinasse not detected by the dichromate COD method (Thalasso et al 1999, Ryznar--Luty et al 2008). In the biodegradation processes conducted in the stirred tank reactor over the temperature range of 27 to 63°C (step 9°C) at controlled pH of 6.5 and 8.0, the highest extent of COD reduction was 88.73% (at 36°C and the pH of 6.5), while betaine was removed within the range of 27 to 54°C at the pH of 8.0, as well as over 27 to 45°C at the pH of 6.5 (Cibis et al 2011).…”

“…The both papers deal with anaerobic biodegradation processes. The paper by Gil-Pena et al (1987) reports on 65% removal of betaine in a laboratory-scale process of vinasse treatment by bacteria isolated from the digestive system of ruminants; the paper by Thalasso et al (1999) informs about 100% betaine removal achieved in a large-scale anaerobic biodegradation of effl uents originating during yeast and citric acid production from molasses. As can be inferred from the analysis of literature data, only a few microorganisms display betaine metabolizing activity (Leblanc et al 2001).…”

Betaine removal during thermo- and mesophilic aerobic batch biodegradation of beet molasses vinasse: Influence of temperature and pH on the progress and efficiency of the process

“…Thalasso et al (1999) and Zub et al (2008) have addressed the problem of industrial-scale anaerobic treatment of the effluent from yeast production involving beet molasses. Thalasso et al (1999) have made a mention informing about industrial-scale treatment of the effluent from citric acid production with beet molasses as the feedstock. According to these investigators, 100% removal of betaine has been attained in both the cases.…”

“…Zub et al (2008) report that betaine underwent degradation but they fail to specify the extent of removal. Thalasso et al (1999) also conducted laboratory investigations into anaerobic batch biodegradation of betaine in a synthetic medium. The time after which betaine had been removed in their study depended to a great extent on the initial concentration of this pollutant.…”