Lipases are enzymes that can be secreted by several microorganisms, making interesting the biodiversity exploration for searching new microorganisms able to produce these enzymes. Many agro-industrial residues can be used as potential substrates for production of enzymes. The main objective of this work was the isolation and screening of microorganisms with potential to produce lipases. Among 24 fungi, five were selected as good lipase producers using tributyrin on agar plates and solid state fermentation of soybean bran. Two of them were isolated from soil samples, another two from soybean bran, and one from dairy products. These fungi were identified by microcultivation technique as from Penicillium and Aspergillus genera. Through random amplified polymorphic DNA technique, the most promising strains could be genetically discriminated, selecting two fungi as good lipase producers but genetically different. One isolated from soybean bran could hydrolyze efficiently triglycerides with fatty acids with different chain length. Another isolated from dairy products was only effective to hydrolyze triglycerides with long-chain fatty acids. Two distinct groups could be verified by means of this technique, comprising the most productive strains and the lowest or nonproductive ones in terms of hydrolytic activity.

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The demand for environmentally friendly products allied with the depletion of natural resources has increased the search for sustainable materials in chemical and pharmaceutical industries. Polyesters are among the most widely used biodegradable polymers in biomedical applications. In this work, aliphatic polyesters (from globalide and ω-pentadecalactone) were synthesized using a new commercial biocatalyst, the low-cost immobilized NS 88011 lipase (lipase B from Candida antarctica immobilized on a hydrophobic support). Results were compared with those obtained under the same conditions using a traditional, but more expensive, commercial biocatalyst, Novozym 435 (lipase B from C. antarctica immobilized on Lewatit VP OC). When NS 88011 was used in the polymerization of globalide, longer reaction times (240 min)-when compared to Novozym 435-were required to obtain high yields (80-90 wt%). However, higher molecular weights were achieved. When poly(ω-pentadecalactone) was synthesized, high yields and molecular weights (130,000 g mol) were obtained and the enzyme concentration showed strong influence on the polyester properties. This is the first report describing NS 88011 in polymer synthesis. The use of this cheaper enzymatic preparation can provide an alternative for polyester synthesis via enzymatic ring-opening polymerization.

The main objective of this work was the optimization of the lipase production by a newly isolated Penicillium sp. in supplemented soybean meal, considering a fixed C/N ratio (6.11). The kinetic behavior of lipase production was also evaluated, quantifying activity at different pH. The production of the enzyme was maximum using a substrate particle size between 1 and 2 mm and inoculum concentration of 2✕10 8 spores • g -1 , at 20°C. Lipase activities of about 200 U • g -1 at pH 4.0 were obtained after 120 h of cultivation, but activities at pH 7.0 as high as 317 U • g -1 could be obtained after 96 h. The activities measured at pH 9.0 were also promising, ranging from 177 to 191 U • g -1 . The results obtained are relevant, since high lipase activities, in a wide range of pH (4.0 to 9.0) were obtained from a newly isolated microorganism in a low-cost fermentation medium. The variation in the C/N ratio at the previously optimized conditions showed that the best results were obtained at C/N of 6.11.