ABSTRACT
As metilcetonas são as principais responsáveis pelo aroma dos chamados "Blue Cheese". Essas substâncias são produzidas por microrganismos adicionados durante o processo de maturação desses queijos. O presente trabalho relata a formação e monitoramento dessas metilcetonas por uma nova linhagem de Aspergillus sp. O biocatalisador foi testado para a produção de metilcetonas adicionando-se 1 ml dessa suspensão em frascos tipo penicilina juntamente com 1 g de creme de leite de vaca e 9 ml do tampão adequado. Foi constatado que as melhores condições de produção de metilcetonas foram suspensão enzimática bruta, pH 4,5 por 96 horas a 30ºC, obtendo-se de 3,4 mg de 2-nonanona por 1 g de creme de leite de vaca.
Subject(s)
Fatty Acids , Flavoring Agents , Aspergillus , BiotransformationABSTRACT
As a relatively prolific producer of GLA, the strain of Mucor sp LB-54 was selected for a study at different growth temperatures in shaker flask culture. The strain used in our experiemnt was capable to accumulate a relatively high amount of intracellular lipid, 20,73 per cent of dry cell weight, and GLA content of 15 per cent of total fatty acids after 5 days of incubation at 28 degree C. As the growth temperature was decreased from 28 to 12 degree C the percentage of GLA increased from 15 to 24 per cent of total fatty acids. In order to optimize the culture conditions for rapid biomass production and lipid production with a high proportion of GLA, the fungus was grown at two temperature combinations associated supplies of carbon source (glucose) in the culture medium. Maximal production of (GLA) (74 mg/l) was obtained from the Mucor sp LB-54 strain after 5 days of incubation at 28 degree C in basal medium following glucose addition (7 per cent w/v) and incubation for an additional 3 days at 12 degree C. The identity of GLA found in the strin of Mucor sp LB-54 was confirmed by the coupled gas chromatography-mass spectrometry.