Chapter 4 © 2012 Soccol et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Data Acquisition Systems in Bioprocesses Carlos Ricardo Soccol, Michele Rigon Spier, Luciana Porto de Souza Vandenberghe, Adriane Bianchi Pedroni Medeiros, Luiz Alberto Junior Letti and Wilerson Sturm Additional information is available at the end of the chapter http://dx.doi.org/10.5772/48466 1. Introduction Data acquisition systems in bioprocesses have distinct working specification. These processes normally involves microbial cells, vegetable cells, mammalian cells, microalgae cells or even enzymatic biochemical reactions, which implicates in time required for biochemical transformations and biomolecules production. Monitoring bioprocesses do not require real time monitor, because low times intervals (minutes or seconds) do not present significant differences on process parameters values. Bioprocesses are important area in the biotechnology and they are applied in many industries. It has many reaction routes available at any time, each one permitting a different distribution of biomolecules and products based on the conditions under which the fermentation process takes place. Control techniques are indicated to improve the productivity, yield and efficiency of the biotechnological processes. In the bioprocesses, it is very important to have a real time analysis of the process for creating a product with high speed, quality and economy. Knowing the parameters which affect biomolecule formation as well as the concentration of the nutrients, and develop or chose a cheap and simple system capable of on line measurements are required for bioprocesses control. This chapter is separated into four parts for better understanding of the systems described. First, the data acquisition system Fersol1 is described and its application in different bioprocesses are also presented. Second, the Fersol2 system is also presented describing its functional components such as sensors, controllers, interface and the software and their functions in this system. Examples of application of Fersol2 are described in the second item. Third part presents other systems already developed and the final part presents biosensors and its applications. Data acquisition system as a source of information about the process behavior and further processing of generating the parameters allows a comparative analysis. Besides the main