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\hypersetup{pdftitle={Bioelectronic Tongues for Measuring Biochemical Oxygen Demand in Water Quality Evaluation},pdfauthor={Kätlin Pitman, Merlin Raud, Timo Kikas},pdfsubject={Tropentag 2016: Abstract},pdfkeywords={Biochemical oxygen demand, biosensor, BOD sensor array, electronic tongue},pdfpagemode=None,colorlinks=true}
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\parbox[b]{13.4cm}{\centering \large{\textbf{Tropentag, September 18-21, 2016, Vienna, Austria}}\\[1ex] \Large{``Solidarity in a competing world ---\\fair use of resources''\\[2ex]}}
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\Large{\textbf{Bioelectronic Tongues for Measuring Biochemical Oxygen Demand in Water Quality Evaluation\footnote{\textbf{Contact Address:} Timo Kikas, Estonian University of Life Sciences, Inst. of Technology, Fr.R.Kreutzwaldi 56, 51014~Tartu, Estonia, \mbox{e-mail}: \email{timo.kikas@emu.ee}}\\[0.8ex]}}
\normalsize{\textsc{Kätlin Pitman, Merlin Raud, Timo Kikas}}
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\begin{itemize*}
\item[]{\small{\textit{Estonian University of Life Sciences, Inst. of Technology, Estonia}}}
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\index[author]{Pitman, Kätlin}
\index[author]{Raud, Merlin}
\index[author]{Kikas, Timo}
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\textbf{Abstract}
\begin{abstract}
\normalsize{
Fresh water is one of the most important natural resources. In order to assure the sustainable usage of water resources, they need to be carefully managed. Environmental management includes water quality evaluation in water and wastewater. One of the most widely used parameters is biochemical oxygen demand (BOD). It is amount of oxygen, which is used to decompose organic compounds in the water. BOD is used to estimate the organic pollution in waters and wastewaters and shows water's self"=clean ability. BOD method is widely used because it does not require expensive equipment. The BOD test lasts 5--7 days or even 21 days. Incubation time this long is not suitable for control of wastewater treatment plants or environmental monitoring. 



In order to shorten the BOD measurement time, a number of biosensors have been proposed. Biosensor is device, which consists of biological sensing element and chemical or physical transducer - usually, microorganisms and Clark"=type dissolved oxygen sensor are used. Unfortunately, traditional oxygen sensor and single culture based BOD biosensors have several limitations: short lifetime, narrow substrate range, low precision, underestimation of BOD etc. One way to get wider substrate range is to use multicultural sensors, but their composition changes in time thus, making it unreliable. Many of the abovementioned limitations can be overcome by using microbial biosensor arrays. Biosensor"=array is a device that consists of several biosensors and produces complex data. Biosensor array that is used in liquid medium is also called bioelectronic tongue. Bioelectronic tongues have wider substrate range that is similar to multicultural sensors, but unlike multicultural sensors, bioelectronic tongues have stable composition and long lifetime that is similar to a single culture sensors. This is achieved by separating cultures with different substrate spectra from each other in an array and using the resulting multidimensional signal from separate sensors in statistical analysis to produce combined information. Statistical analysis may be linear or non"=linear however, the most used methods are principal component analysis, partial least squares and principal component regression. 



Purpose of this report is to give overview of BOD measurements and show that bioelectronic tongues are useful devices in environmental management.



}

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\noindent \textbf{Keywords:} Biochemical oxygen demand, biosensor, BOD sensor array, electronic tongue
\index[key]{Biochemical oxygen demand}
\index[key]{Biosensor}
\index[key]{BOD sensor array}
\index[key]{Electronic tongue}
\end{document}
