Biologia

Nano-Tubular Cellulose for Bioprocess Technology Development
Athanasios A. Koutinas1*, Vasilios Sypsas1, Panagiotis Kandylis1, Andreas Michelis1, Argyro Bekatorou1, Yiannis Kourkoutas2, Christos Kordulis3,4, Alexis Lycourghiotis3, Ibrahim M. Banat5, Poonam Nigam5, Roger Marchant5, Myrsini Giannouli6, Panagiotis Yianoulis6
1 Food Biotechnology Group, Department of Chemistry, University ofPatras, Patras, Greece, 2 Department of Molecular Biology, Democritus University of Thrace, Alexandroupolis, Greece, 3 Group of Catalysis and Interfacial Chemistry for Environmental Applications, University of Patras, Patras, Greece, 4 Institute of Chemical Engineering and High Temperature Chemical Processes (FORTH/ICE-HT), Patras, Greece, 5 School of Biomedical Sciences, University of Ulster,Coleraine, United Kingdom, 6 Department of Physics, University of Patras, Patras, Greece

Abstract
Delignified cellulosic material has shown a significant promotional effect on the alcoholic fermentation as yeast immobilization support. However, its potential for further biotechnological development is unexploited. This study reports the characterization of this tubular/porous cellulosic material, whichwas done by SEM, porosimetry and X-ray powder diffractometry. The results showed that the structure of nano-tubular cellulose (NC) justifies its suitability for use in ‘‘cold pasteurization’’ processes and its promoting activity in bioprocessing (fermentation). The last was explained by a glucose pump theory. Also, it was demonstrated that crystallization of viscous invert sugar solutions duringfreeze drying could not be otherwise achieved unless NC was present. This effect as well as the feasibility of extremely low temperature fermentation are due to reduction of the activation energy, and have facilitated the development of technologies such as wine fermentations at home scale (in a domestic refrigerator). Moreover, NC may lead to new perspectives in research such as the developmentof new composites, templates for cylindrical nano-particles, etc.
Citation: Koutinas AA, Sypsas V, Kandylis P, Michelis A, Bekatorou A, et al. (2012) Nano-Tubular Cellulose for Bioprocess Technology Development. PLoS ONE 7(4): e34350. doi:10.1371/journal.pone.0034350 Editor: Vipul Bansal, RMIT University, Australia Received October 21, 2011; Accepted February 27, 2012; Published April 9, 2012Copyright: ß 2012 Koutinas et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The authors have no support or funding to report. Competing Interests: The authors have declared that no competing interestsexist. * E-mail: a.a.koutinas@upatras.gr

Introduction
Research on bioprocess technology development has been extensive during the last decades; however most of these technologies have not been used at industrial level. The main problems associated with these technologies are related to productivity, ease of industrial application and production cost. However there are still opportunities touse abundant, low cost materials with specific chemical or nano-mechanical properties to create multiple new, effective bioprocessing systems. One of the major problems of food and drug production is the use of the relatively costly pasteurization processes. In addition to high operational cost, pasteurization reduces the nutritional quality of food products. However due to its importance,pasteurization is extensively used despite these disadvantages. Only in some food bioprocesses like wine production, membranes [1] are used to remove e.g. Leuconostoc oenos cells but they have a high cost and are not easy to handle at industrial level. Alternatively, if a nano-tubular solid of food grade purity, could be used to remove microbial cells through cell entrapment and immobilization at ambient...