-This paper provides an overview regarding the main aspects of seed lipases, such as the reactions catalyzed, physiological functions, specificities, sources and applications. Lipases are ubiquitous in nature and are produced by several plants, animals and microorganisms. These enzymes exhibit several very interesting features, such as low cost and easy purification, which make their commercial exploitation as industrial enzymes a potentially attractive alternative. The applications of lipases in food, detergents, oils and fats, medicines and fine chemistry, effluent treatment, biodiesel production and in the cellulose pulp industry, as well as the main sources of oilseed and cereal seed lipases, are reviewed.

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Grape pomace (GP) is a polyphenolic-rich byproduct of wine production. As most polyphenolics are either bound to cellular matrices or present as free polymeric forms, treatment with hydrolytic enzymes may act to increase GP functionalities. The aim of this study was to examine the impact of tannase alone (T), pectinase plus cellulase (PC) or a mixture of them (TPC) on the hydrolysis of polyphenolics in red GP (RGP), white GP (WGP), and mixed GP (MGP) from Brazilian wine production, as well as antioxidant activity of the products. T was the most potent in increasing total polyphenols in GP by liberating gallic acid, caffeic acid, quercetin, and trans-resveratrol. PC increased the catechin content in RGP and TPC increased the procyanidin B2 in WGP. T treatment of GP was most effective in increasing antioxidant activity. In conclusion, the enzymatic treatment, particularly with T, increases the polyphenolic content and antioxidant activity of GP.

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Recebido em 18/5/04; aceito em 12/11/04; publicado na web em 13/4/05 POTENTIAL OF ENANTIOSELECTIVE BIOCATALYSIS BY MICROBIAL LIPASES. Microbial lipases have a great potential for commercial applications due to their stability, selectivity and broad substrate specificity because many non-natural acids, alcohols or amines can be used as the substrate. Three microbial lipases isolated from Brazilian soil samples (Aspergillus niger; Geotrichum candidum; Penicillium solitum) were compared in terms of their stability and as biocatalysts in the enantioselective esterification using racemic substrates in organic medium. The lipase from Aspergillus niger showed the highest activity (18.2 U/mL) and was highly thermostable, retaining 90% and 60% activity at 50 o C and 60 o C after 1 hour, respectively. In organic medium, this lipase provided the best results in terms of enantiomeric excess of the (S)-active acid (ee = 6.1%) and conversion value (c = 20%) in the esterification of (R,S)-ibuprofen with 1-propanol in isooctane. The esterification reaction of the racemic mixture of (R,S)-2-octanol with decanoic acid proceeded with high enantioselectivity when lipase from Aspergillus niger (E = 13.2) and commercial lipase from Candida antarctica (E = 20) were employed.Keywords: lipases; enantioselectivity; (R,S)-ibuprofen. INTRODUÇÃOA biocatálise é hoje um dos campos mais promissores dentro das novas tecnologias para síntese de compostos de alto valor agregado. A exploração da biodiversidade na busca de novos catalisadores por técnicas de seleção de microrganismos, de plantas ou células animais representam os métodos tradicionais de descoberta de novas enzimas para o desenvolvimento da biocatálise em escala industrial 1 . Os microrganismos neste caso são de particular interesse devido ao curto período de geração, à grande diversidade de processos metabólicos e enzimas envolvidas e, não há um número limitado de microrganismos na natureza que possam ser testados, os quais são bastante diferentes entre si. Microrganismos isolados em território brasileiro têm demonstrado excelente potencial biocatalisador frente a diferentes substratos orgânicos de interesse, como por ex. na hidrólise de óleos marinhos 2,3 , na síntese de ésteres de ácidos graxos poliinsaturados 4 e de ésteres de aroma 5 .Dentre as enzimas hidrolíticas de maior interesse estão as lipases (glicerol ester hidrolase E C. 3.1.1.3), que são biocatalisadores versáteis capazes de catalisar diferentes reações, tanto em meio aquoso como em meio orgânico, com teor de água restrito. Entre as lipases de vegetais, animais e microbianas, estas últimas são as mais utilizadas e, na sua grande maioria, não são nocivas a saúde humana, sendo reconhecidas como "Generally Regarded as Save -GRAS" 6 . Do ponto de vista industrial, os fungos são especialmente valorizados porque as enzimas por eles produzidas normalmente são extracelulares, o que facilita sua recuperação do meio de fermentação 7 . Os trabalhos replatados em literatura sobre lipases fúngicas são numerosos, sendo que os mais ...

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The use of enzymes in juice industry has contributed in increasing the yield and production of various types of juices. The addition pectinases aims in particular to degrade the pectic substances, in the cell wall and middle lamella of the cells of plants, aiming to minimise the impacts of these compounds on the characteristics of the final product, such as colour, turbidity and viscosity. Enzymes able to remove bitterness of citrus juice, extract pigments, among other applications, have also had great interest in the juice industry.

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