Enzymatic deacetylation of chitin by extracellular chitin deacetylase from a newly screened Mortierella sp. DY-52.
Among more than a hundred colonies of fungi isolated from soil samples, DY-52 has been screened as an extracellular chitin deacetylase (CDA) producer. The isolate was further identified as Mortierella sp., based on the morphological properties and the nucleotide sequence of its 18S rRNA gene. The fungus exhibited maximal growth in yeast peptone glucose (YPD) liquid medium containing 2% of glucose at pH 5.0 and 28 degrees C with 150 rpm. The CDA activity of DY-52 was maximal (20 U/mg) on the 3rd day of culture in the same medium. The CDA was inducible by addition of glucose and chitin. The enzyme contained two isoforms of molecular mass 50 kDa and 59 kDa. This enzyme showed a maximal activity at pH 5.5 and 60 degrees C. In addition, it had a pH stability range of 4.5-8.0 and a temperature stability range of 4-40 degrees C. The enzyme was enhanced in the presence of Co2+ and Ca2+. Among various substrates tested, WSCT-50 (water-soluble chitin, degree of deacetylation 50%), glycol chitin, and crab chitosan (DD 71-88%) were deacetylated. Moreover, the CDA can handle N-acetylglucosamine oligomers (GlcNAc)2-7.
Kim
Young-Ju
YJ
Glucosamine Saccharide Materials-National Research Laboratory (GSM-NRL), Division of Applied Bioscience and Biotechnology,Institute of Agricultural Science and Technology, Chonnam National University, Gwangju 500-757, Korea.
Zhao
Yong
Y
Oh
Kyung-Taek
KT
Nguyen
Van-Nam
VN
Park
Ro-Dong
RD
D000581:Amidohydrolases / Q000737:chemistry / Q000378:metabolism*; D002686:Chitin / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D004271:DNA, Fungal / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D020094:Mortierella / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D021381:Protein Transport; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012988:Soil Microbiology; D013379:Substrate Specificity; D013696:Temperature
D003470:Culture Media; D004271:DNA, Fungal; D004275:DNA, Ribosomal; D005656:Fungal Proteins; D012337:RNA, Ribosomal, 18S; D002686:Chitin; D000581:Amidohydrolases; C019866:chitin deacetylase