Fatty acid preference of mycelium-bound lipase from a locally isolated strain of Geotrichum candidum

Abstract

Mycelium-bound lipase (MBL) was prepared using a strain of Geotrichum candidum isolated from local soil. At the time of maximum lipase activity (54 h), the mycelia to which the lipase was bound were harvested by filtration and centrifugation. Dry MBL was prepared by lyophilizing the mycelia obtained. The yield of MBL was 3.66 g/l with a protein content of 44.11 mg/g. The lipase activity and specific lipase activity were 22.59 and 510 U/g protein, respectively. The moisture content of the MBL was 3.85%. The activity of free (extracellular) lipase in the culture supernatant (after removal of mycelia) was less than 0.2 U/ml. The MBL showed selectivity for oleic acid over palmitic acid during hydrolysis of palm olein, indicating that the lipase from G. candidum displayed high substrate selectivity for unsaturated fatty acid containing a cis-9 double bond, even in crude form. This unique specificity of MBL could be a direct, simple and inexpensive way in the fats and oil industry for the selective hydrolysis or transesterification of cis-9 fatty acid residues in natural triacylglycerols.

Differences in hydrolytic abilities of two crude lipases from Geotrichum candidum 4013

“…In contrast, the cell-bound lipase possesses selectivity to saturated fatty acids. A similar finding was observed when the mycelium-bound lipase from G. candidum (IMI 387428) was used as a biocatalyst during hydrolysis of palm olein (Loo et al, 2007). The lipase showed selectivity for oleic acid over palmitic acid, indicating that it displayed high substrate selectivity for unsaturated fatty acid containing a cis-9 double bond, even in crude form.…”

“…Although they have attracted great attention, as can be seen from the many previous works (Loo et al 2007;Song et al 2008), it is still necessary to add more interesting and helpful information on the specificities of lipases, especially those lipases from different microorganisms. Triacylglycerols, fatty acid methyl esters and p-nitrophenyl esters were used as substrates in lipase hydrolysis trials.…”

A Review on Geotrichum Lipases: Production, Purification, Immobilization and Applications

“…The concentrations used vary greatly, but the range from 0.1 to 5.0 % w/w is more commonly used, and organic sources are added in higher quantities than inorganic sources . Concentrations (% w/w) of: 5.0 of peptone; 2.0 of yeast extract and 0.1 of NaNO 3 and 0.5 of NH 4 NO 3 are commonly applied in the lipase production [43][44][45][46]49,57 ; however, optimized studies about medium composition reduced or eliminated some nitrogen sources in the process. Burket et al and Maldonado et al showed that 3.58 % w/w of peptone is enough to obtain a high level of lipase activity from G. candidum.…”

“…The inoculum is another important variable in the lipase production from Geotrichum, and the liquid form 45,46 , used at 10 % (v/v) 47 or 5 % (v/v) 48 , is frequently applied. However, this type of inoculum can be an obstacle to the homogenization and standardization of inoculum, as shown by Resende-Maldonado et al 49 The authors proposed the utilization of an initial solid inoculum (with a specific area) followed by an intermediate liquid inoculum that reduced the variability of the lipase activity by 33 % during the fermentation.…”

“…Studies in stirred tank bioreactor indicated that aeration of 1.0 vvm or lower are the best conditions for lipase production from Geotrichum candidum [51][52][53]60 . The low level of oxygen is also efficient in shaken flasks; several studies have indicated agitation conditions below 200 rpm for lipase production from Geotrichum, which reduces the quantity of dissolved oxygen 46,47,54,56,[62][63][64] . Geotrichum is a mesophilic yeast and most studies have shown that temperatures near 30 °C are more appropriate for its growth and lipase production.…”