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Isolation and characterization of Gibberella intermedia CA3‐1, a novel and versatile nitrilase‐producing fungus
Author(s) -
Wu Yan,
Gong JinSong,
Lu ZhenMing,
Li Heng,
Zhu XiaoYan,
Li Hui,
Shi JingSong,
Xu ZhengHong
Publication year - 2013
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201200143
Subject(s) - nitrilase , chemistry , substrate (aquarium) , hydrolysis , biocatalysis , enzyme , biochemistry , stereochemistry , biotransformation , biology , catalysis , reaction mechanism , ecology
Nitrilase‐mediated biocatalysis has attracted substantial attention for its application in carboxylic acid production in recent years. In the present study, the fungus CA3‐1 was isolated and identified as Gibberella intermedia based on its morphology, its 18S ribosomal DNA (rDNA), and internal transcribed spacer (ITS) sequences. The enzymatic properties of G. intermedia resting cells were determined, and the optimum activity was achieved at 40 °C with pH 7.6. The half‐lives of the nitrilase at 30, 40, and 50 °C were 231.1, 72.9, and 6.4 h, respectively. This Gibberella nitrilase showed a wide substrate spectrum with high specificity for heterocyclic and aliphatic nitriles. It remained extremely active in 5% propanol. The presence of Ag + , Hg 2+ , and excess substrate inhibited the nitrilase activity, whereas Fe 2+ , Mn 2+ , and Li + improved enzyme activity. 3‐Cyanopyridine (50 mM) was hydrolyzed into nicotinic acid within 30 min, whereas only <5% of nicotinamide was detected. The results show that this fungal nitrilase is a promising candidate for commercial application in nicotinic acid production.