Several polyunsaturated fatty acids (PUFA) belonging to the ômega 6 series, such as cis-6,9,12 gamma-linolenic acid, as well as those of the ômega 3 series, such as cis-5,8,11,14,17-eicosapentaenoic acid and cis-4,7,10,13,16,19-docosahexaenoic acid are of considerable interest due to their nutritional and therapeutic properties. Methods used for the concentration of PUFA from natural sources include urea adduct formation, solvent winterization, supercritical fluid extraction and lipase-catalyzed reaction. Lipases are known to have little reactivity on PUFA and these acids can be enriched by selective hydrolysis, direct esterification of glycerol with PUFA and interesterification. Since lipase reactions are advantageous with respect to fatty acid, positional specificities and mild incubation condition, these enzymes are considered to be suitable for the production of PUFA concentrates for medical purposes.

A linhagem de Mucor sp LB-54, considerada uma potencial produtora de ácido gama-linolênico (GLA), foi selecionada para o estudo de diferentes temperaturas de cultivo em agitador rotativo. A linhagem usada neste experimento era capaz de acumular uma quantidade alta de lipídeos intracelulares, 20,73 % do peso seco de biomassa e conteúdo de GLA de 15 % dentre os ácidos graxos totais de sua constituição após 5 dias de incubação à 28°C. Quando a temperatura de cultivo foi diminuída de 28oC para 12°C, o conteúdo de GLA aumentou de 15 para 24% dentre os ácidos graxos totais de sua constituição. Com o objetivo de otimizar as condições de cultivo para a produção rápida de biomassa e produção de lipídeos contendo conteúdo alto de GLA, o fungo foi cultivado em duas combinações de temperaturas associadas com a suplementação de fonte de carbono (glicose). A produção máxima de GLA (74mg/l) pela linhagem de Mucor sp LB-54 foi obtida após 5 dias de incubação à 28°C em meio base, seguida da adição de glicose (7% p/v) no meio de cultura e uma posterior incubação por mais 3 dias a 12°C. A identidade do GLA foi confirmada pelo sistema acoplado cromatógrafo à gás - espectrômetro de massa.

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 experiment was capable to accumulate a relatively high amount of intracellular lipid, 20.73 % of dry cell weight, and GLA content of 15 % of total fatty acids after 5 days of incubation at 28°C. As the growth temperature was decreased from 28 to 12°C the percentage of GLA increased from 15 to 24 % 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°C in basal medium following glucose addition (7 % w/v) and incubation for an additional 3 days at 12°C. The identity of GLA found in the strain of Mucor sp LB-54 was confirmed by the coupled gas chromatography-mass spectrometry