title: L-methioninase production by filamentous fungi: I-screening and optimization under submerged conditions.
abstract: Findings show 21 fungal isolates belonging to eight genera recovered from Egyptian soils that have the potential to attack L-methionine under submerged conditions. Aspergillus flavipes had the most methioninolytic activity, giving the highest yield of L-methioninase (10.78 U/mg protein), rate of methionine uptake (93.0%), and growth rate (5.0 g/l), followed by Scopulariopsis brevicaulis and A. carneus. The maximum L-methioninase productivity (11.60 U/mg protein) by A. flavipes was observed using L-methionine (0.8%) as an enzyme-inductive agent and glucose (1%) as a co-dissimilated carbon source. A significant reduction in L-methioninase biosynthesis by A. flavipes was detected using carbon-free medium, suggesting the lack of ability to use L-methionine as a carbon and nitrogen source. Potassium dihydrogen phosphate (0.25%), the best source of phosphorus, favors enzyme biosynthesis and enhances the level of methionine uptake by A. flavipes. The maximum L-methioninase productivity (12.58 U/mg protein) and substrate uptake (95.6%) were measured at an initial pH of 7.0.
authors.affiliation: Department of Botany and Microbiology, Faculty of Science, Zagazig University, Zagazig, Egypt.
authors.forename: Salwa A
authors.initials: SA
authors.lastname: Khalaf
authors.forename: Ashraf S A
authors.initials: AS
authors.lastname: El-Sayed
mesh_terms: D001230:Aspergillus / Q000201:enzymology / Q000302:isolation & purification / Q000378:metabolism; D018533:Biomass; D002244:Carbon / Q000378:metabolism; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media / Q000378:metabolism; D046508:Culture Techniques; D005285:Fermentation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005658:Fungi / Q000201:enzymology* / Q000302:isolation & purification* / Q000378:metabolism; D008715:Methionine / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D012988:Soil Microbiology
chemical_list: D003470:Culture Media; D005656:Fungal Proteins; D010758:Phosphorus; D002244:Carbon; D008715:Methionine; D013437:Carbon-Sulfur Lyases; C021558:L-methionine gamma-lyase; D009584:Nitrogen