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 Edmund Cibis * , Agnieszka Ryznar-Luty, Ma1gorzata Krzywonos, Krzysztof Lutos1awski, Tadeusz Mi  skiewicz Department of Bioprocess Engineering, Wroclaw University of Economics, Komandorska 118/120, 53-345 Wroclaw, Poland article info Article history: Received 27 July 2010 Received in revised form 4 January 2011 Accepted 6 February 2011 Available online 1 March 2011 Keywords: Betaine Vinasse Aerobic biodegradation Thermophilic Mesophilic Bacillus abstract The key issue in achieving a high extent of biodegradation of beet molasses vinasse is to establish the conditions for the assimilation of betaine, which is the main pollutant in this high-strength industrial effluent. In the present study, aerobic batch biodegradation was conducted over the temperature range of 27e63  C (step 9  C), at a pH of 6.5 and 8.0, using a mixed culture of bacteria of the genus Bacillus. Betaine was assimilated at 27e54  C and the pH of 8.0, as well as at 27e45  C and the pH of 6.5. The processes where betaine was assimilated produced a high BOD 5 removal, which exceeded 99.40% over the temperature range of 27e45  C at the pH of 8.0, as well as at 27  C and the pH of 6.5. Maximal COD removal (88.73%) was attained at 36  C and the pH of 6.5. The results indicate that the process can be applied on an industrial scale as the first step in the treatment of beet molasses vinasse. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Beet molasses is used for ethyl alcohol production primarily in the European countries. In 2006 and 2007, the European Union made use of beet molasses and sugar beets as substrates to obtain 29% of the total ethyl alcohol volume produced within this time span (Balat and Balat, 2009). It is essential to note that the European Union is the third largest world ethanol producer following the United States and Brazil (F.O. Licht’s World Ethanol and Biofuels Report, 2008). In Poland, approximately 20% of the ethanol volume is produced with beet molasses as a substrate ( _ Zmuda, Polish Ministry of Agriculture, 2008, personal communication). Stillage, a troublesome residue from distilling off spirit, is the main waste generated in the course of ethanol production. Stillage from sugar-based feedstocks, e.g. beet molasses vinasse and cane- based vinasse, can be used in agriculture as fodder. However, compared with stillage from starch-based feedstocks characterized by a high potassium content they have a lower nutritive value (Wilkie et al., 2000). Another agricultural application for vinasse is the use as a fertilizer, which is common practice in Brazil (cane- based vinasse), Eastern Europe and in some of the western Euro- pean countries (Lewicki, 2001; Wheals et al., 1999). It is worthy of mention that crop growth follows a seasonal pattern and depends on the weather conditions, which poses limitations on the direct use of vinasse for the fertilization of arable land. Another method of solving the vinasse problem includes biodegradation, which is very popular in India (cane-based vinasse). The biodegradation of vinasse performed in the distill- eries of India consists of at least two stages: methanation and an aerobic process. The effluent from the aerobic process is either discharged (upon dilution) into surface waters or sprayed for field irrigation. In some instances the dilution procedure is replaced with an additional treatment stage (Satyawali and Balakrishnan, 2008). As yet, the treatment of beet molasses vinasse by biodeg- radation has not found wide acceptance. Regardless of whether it originated from sugar cane or sugar beets, vinasse is a high- strength effluent with a chemical oxygen demand (COD) frequently exceeding 100 g O 2 /l (Ryznar-Luty et al., 2008; Satyawali and Balakrishnan, 2008). Vinasse also contains large amounts of other * Corresponding author. Tel.: þ48 71 3680285; fax: þ48 71 3680753. E-mail addresses: edmund.cibis@ue.wroc.pl (E. Cibis), agnieszka.ryznar@ue. wroc.pl (A. Ryznar-Luty), malgorzata.krzywonos@ue.wroc.pl (M. Krzywonos), krzysztof.lutoslawski@ue.wroc.pl (K. Lutos1awski), tadeusz.miskiewicz@ue.wroc.pl (T. Mi skiewicz). Contents lists available at ScienceDirect Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman 0301-4797/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.jenvman.2011.02.009 Journal of Environmental Management 92 (2011) 1733e1739