Heterologous Expression of a Hyperthermophilic α-Amylase in Xanthan Gum Producing Xanthomonas campestris Cells Zoe Konsoula & Maria Liakopoulou-Kyriakides & Angelos Perysinakis & Panayiota Chira & Amalia Afendra & Constantin Drainas & Dimitrios A. Kyriakidis Received: 13 July 2007 / Revised: 27 November 2007 / Accepted: 30 November 2007 # Humana Press Inc. 2007 Abstract A hyperthermophilic α-amylase encoding gene from Pyrococcus woesei was transferred and expressed in Xanthomonas campestris ATCC 13951. The heterologous α- amylase activity was detected in the intracellular fraction of X. campestris and presented similar thermostability and catalytic properties with the native P. woesei enzyme. The recombinant α- amylase was found to be stable at 90 °C for 4 h and within the same period it retained more than 50% of its initial activity at 110 °C. Furthermore, X. campestris transformants produced similar levels of recombinant α-amylase activity regardless of the carbon source present in the growth medium, whereas the native X. campestris α-amylase production was highly dependent on starch availability and it was suppressed in the presence of glucose or other reducing sugars. On the other hand, xanthan gum yield, which appeared to be similar for both wild type and recombinant X. campestris strains, was enhanced at higher starch or glucose concentrations. Evidence presented in this study supports that X. campestris is a promising cell factory for the co-production of recombinant hyperthermophilic α-amylase and xanthan gum. Appl Biochem Biotechnol DOI 10.1007/s12010-007-8115-x Z. Konsoula : M. Liakopoulou-Kyriakides (*) Department of Chemistry, Faculty of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece e-mail: markyr@eng.auth.gr A. Perysinakis : P. Chira : C. Drainas Sector of Organic Chemistry and Biochemistry, Faculty of Chemistry, University of Ioannina, Ioannina 45110, Greece A. Afendra Department of Biological Applications and Technologies, University of Ioannina, Ioannina 45110, Greece D. A. Kyriakidis Laboratory of Biochemistry, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece D. A. Kyriakidis The National Hellenic Research Foundation, 48 Vas. Constantinou, Athens 11635, Greece