title: Heterologous expression of a hyperthermophilic alpha-amylase in xanthan gum producing Xanthomonas campestris cells.
abstract: A hyperthermophilic alpha-amylase encoding gene from Pyrococcus woesei was transferred and expressed in Xanthomonas campestris ATCC 13951. The heterologous alpha-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 alpha-amylase was found to be stable at 90 degrees C for 4 h and within the same period it retained more than 50% of its initial activity at 110 degrees C. Furthermore, X. campestris transformants produced similar levels of recombinant alpha-amylase activity regardless of the carbon source present in the growth medium, whereas the native X. campestris alpha-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 alpha-amylase and xanthan gum.
authors.affiliation: Department of Chemistry, Faculty of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Konsoula
authors.forename: Maria
authors.initials: M
authors.lastname: Liakopoulou-Kyriakides
authors.forename: Angelos
authors.initials: A
authors.lastname: Perysinakis
authors.forename: Panayiota
authors.initials: P
authors.lastname: Chira
authors.forename: Amalia
authors.initials: A
authors.lastname: Afendra
authors.forename: Constantin
authors.initials: C
authors.lastname: Drainas
authors.forename: Dimitrios A
authors.initials: DA
authors.lastname: Kyriakidis
mesh_terms: D015870:Gene Expression / Q000502:physiology*; D011135:Polysaccharides, Bacterial; D013696:Temperature; D016959:Xanthomonas campestris / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D000516:alpha-Amylases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D011135:Polysaccharides, Bacterial; D000516:alpha-Amylases; C002563:xanthan gum