title: Isolation and characterization of Gibberella intermedia CA3-1, a novel and versatile nitrilase-producing fungus.
abstract: 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.
authors: The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, PR China.
authors: Yan
authors: Y
authors: Wu
authors: Jin-Song
authors: JS
authors: Gong
authors: Zhen-Ming
authors: ZM
authors: Lu
authors: Heng
authors: H
authors: Li
authors: Xiao-Yan
authors: XY
authors: Zhu
authors: Hui
authors: H
authors: Li
authors: Jing-Song
authors: JS
authors: Shi
authors: Zheng-Hong
authors: ZH
authors: Xu
mesh_terms: D000619:Aminohydrolases / Q000378:metabolism*; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D020536:Enzyme Activators / Q000032:analysis; D004791:Enzyme Inhibitors / Q000032:analysis; D020459:Genes, rRNA; D005874:Gibberella / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010802:Phylogeny; D012331:RNA, Fungal / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D012331:RNA, Fungal; D012337:RNA, Ribosomal, 18S; D000619:Aminohydrolases; C021867:nitrilase
keywords: Biocatalysis; Gibberella intermedia; Identification; Nicotinic acid; Nitrilase