title: Amylase production by Preussia minima, a fungus of endophytic origin: optimization of fermentation conditions and analysis of fungal secretome by LC-MS.
abstract: BACKGROUND
  Environmental screening programs are used to find new enzymes that may be utilized in large-scale industrial processes. Among microbial sources of new enzymes, the rationale for screening fungal endophytes as a potential source of such enzymes relates to the hypothesised mutualistic relationship between the endophyte and its host plant. There is a need for new microbial amylases that are active at low temperature and alkaline conditions as these would find industrial applications as detergents.
  
  
  RESULTS
  An α-amylase produced by Preussia minima, isolated from the Australian native plant, Eremophilia longifolia, was purified to homogeneity through fractional acetone precipitation and Sephadex G-200 gel filtration, followed by DEAE-Sepharose ion exchange chromatography. The purified α-amylase showed a molecular mass of 70 kDa which was confirmed by zymography. Temperature and pH optima were 25°C and pH 9, respectively. The enzyme was activated and stabilized mainly by the metal ions manganese and calcium. Enzyme activity was also studied using different carbon and nitrogen sources. It was observed that enzyme activity was highest (138 U/mg) with starch as the carbon source and L-asparagine as the nitrogen source. Bioreactor studies showed that enzyme activity was comparable to that obtained in shaker cultures, which encourages scale-up fermentation for enzyme production. Following in-gel digestion of the purified protein by trypsin, a 9-mer peptide was sequenced and analysed by LC-ESI-MS/MS. The partial amino acid sequence of the purified enzyme presented similarity to α-amylase from Magnaporthe oryzae.
  
  
  CONCLUSIONS
  The findings of the present study indicate that the purified α-amylase exhibits a number of promising properties that make it a strong candidate for application in the detergent industry. To our knowledge, this is the first amylase isolated from a Preussia minima strain of endophytic origin.
authors.forename: Bita
authors.initials: B
authors.lastname: Zaferanloo
authors.forename: Shatabdi
authors.initials: S
authors.lastname: Bhattacharjee
authors.forename: Mahmood M
authors.initials: MM
authors.lastname: Ghorbani
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Mahon
authors.affiliation: Department of Chemistry and Biotechnology, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia. epalombo@swin.edu.au.
authors.forename: Enzo A
authors.initials: EA
authors.lastname: Palombo
mesh_terms: D000681:Amylases / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D001203:Ascomycota / Q000201:enzymology* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D005591:Chemical Fractionation; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D002853:Chromatography, Liquid; D060026:Endophytes / Q000201:enzymology / Q000378:metabolism; D020536:Enzyme Activators; D004795:Enzyme Stability; D005285:Fermentation; D005656:Fungal Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008345:Manganese / Q000378:metabolism; D013058:Mass Spectrometry; D008970:Molecular Weight; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D020536:Enzyme Activators; D005656:Fungal Proteins; D008345:Manganese; D000681:Amylases; D002118:Calcium