Enzyme and Microbial Technology 50 (2012) 215–220 Contents lists available at SciVerse ScienceDirect Enzyme and Microbial Technology jou rn al h om epage: www.elsevier.com/locate/emt Biosensor analyzer for BOD index express control on the basis of the yeast microorganisms Candida maltosa, Candida blankii, and Debaryomyces hansenii Viacheslav Arlyapov a , Stanislav Kamanin a , Olga Ponamoreva a , Anatoly Reshetilov b,∗ a Tula State University, Pr. Lenina 92, Tula, 300600 Russia b Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pr. Nauki 5, Pushchino, Moscow Region, 142290 Russia a r t i c l e i n f o Article history: Received 28 February 2011 Received in revised form 22 November 2011 Accepted 11 January 2012 Keywords: BOD sensors Yeast Candida maltosa Yeast Candida blankii Yeast Debaryomyces hansenii a b s t r a c t The parameters of biosensors based on the yeast strains Candida maltosa VKM Y-2359, Candida blankii VKM Y-2675, and Debaryomyces hansenii VKM Y-2482 for biochemical oxygen demand (BOD) detection are compared. The catalytic activity of the strains was analyzed in relation to the growth phase. The possibility of using D. hansenii as a basis for receptor element of a biosensor for BOD detection in municipal and biotechnological wastewaters was shown. © 2012 Elsevier Inc. All rights reserved. 1. Introduction The most important integral characteristic of water quality is biochemical oxygen demand (BOD), i.e., the amount of dissolved oxygen required for oxidation of all biodegradable organic com- pounds [1]. BOD assessment is an empirical test employing the standard laboratory procedure for determining oxygen uptake in analyzed water samples. The conventional method of BOD detec- tion requires incubation of an oxygen-saturated sample for at least 5 days [2]. Due to considerable time it takes, the method is not adequate under modern conditions, because the results of analysis are made available with a significant delay. Hence, environmen- tally hazardous situations can occur, when an emergency inflow of polluted waters to water treatment facilities passes unnoticed or, the other way round, they are insufficiently purified in the course of regeneration. Alternatives are express methods of BOD detection by biosen- sor analyzers based on microorganisms that can metabolize a wide range of organic compounds [3]. At present, commercially pro- duced biosensor analyzers detect BOD within a few minutes in the range of 2–500 mg/dm 3 [4–6]. The bioreceptor elements of BOD sensors are based on either pure cultures with certain functional properties (a wide range of ∗ Corresponding author. Fax: +7 495 956 33 70. E-mail addresses: gwinbleidd@rambler.ru (V. Arlyapov), gwinbleidd@rambler.ru (S. Kamanin), olga@tsu.tula.ru (O. Ponamoreva), anatol@ibpm.pushchino.ru (A. Reshetilov). oxidized substrates, resistance to negative environmental factors, or specificity to certain wastes), or a mixture of identified microor- ganisms (artificial associations), or activated sludge. Each of these approaches has its own advantages and disadvantages. Yeasts are the preferable biomaterial for nearly all types of biosensors as they oxidize a broad spectrum of substances, are resistant to neg- ative environmental factors, and can function in the recognizing biosensor element for a long time. Thus, a sensor based on the yeast Saccharomyces cerevisiae encapsulated in calcium alginate was described in [7]. The sensor was characterized by a satisfac- tory stability and was used for the analysis of wastewater samples. A good correlation between BOD values determined by the biosen- sor and by the standard BOD 5 approach was shown. In [8], a BOD sensor based on the yeast Arxula adeninovorans immobilized in a polyurethane-based polymer, polycarbomoyl sulfonate, was used for BOD detection in municipal and industrial wastewaters from different sources, including wastes with a high salt content. Appli- cation of various yeast strains for BOD sensors development is not confined to these examples [9–11]. Development of biosensor methods of analysis places demands on the quality of BOD sensors and accuracy of measurements, which primarily depend on the properties of bioreceptor elements. The promising research trend is to examine the possibility of using bioreceptor elements that would improve measurement quality. This work used the following yeast strains: Candida maltosa VKM Y-2359, Candida blankii VKM Y-2675, and Debaryomyces hansenii VKM Y-2482. According to the literature data, the yeasts C. mal- tosa, C. blankii, and D. hansenii have a broad substrate specificity and can oxidize many alcohols, carbohydrates, amino acids, and 0141-0229/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.enzmictec.2012.01.002