RESUMO

The competitive colonization of bacteria on similar ecological niches has a significant impact during their establishment. The synthesis speeds of different chemical classes of molecules during early competitive colonization can reduce the number of competitors through metabolic effects. In this work, we demonstrate for the first time that Kosakonia cowanii Cp1 previously isolated from the seeds of Capsicum pubescens R. P. produced volatile organic compounds (VOCs) during competitive colonization against Pectobacterium aroidearum SM2, affecting soft rot symptoms in serrano chili (Capsicum annuum L.). The pathogen P. aroidearum SM2 was isolated from the fruits of C. annuum var. Serrano with soft rot symptoms. The genome of the SM2 strain carries a 5,037,920 bp chromosome with 51.46% G + C content and 4925 predicted protein-coding genes. It presents 12 genes encoding plant-cell-wall-degrading enzymes (PCDEWs), 139 genes involved in five types of secretion systems, and 16 genes related to invasion motility. Pathogenic essays showed soft rot symptoms in the fruits of C. annuum L., Solanum lycopersicum, and Physalis philadelphica and the tubers of Solanum tuberosum. During the growth phases of K. cowanii Cp1, a mix of VOCs was identified by means of HS-SPME-GC-MS. Of these compounds, 2,5-dimethyl-pyrazine showed bactericidal effects and synergy with acetoin during the competitive colonization of K. cowanii Cp1 to completely reduce soft rot symptoms. This work provides novel evidence grounding a better understanding of bacterial interactions during competitive colonization on plant tissue, where VOC synthesis is essential and has a high potential capacity to control pathogenic microorganisms in agricultural systems.

RESUMO

Guava juice is cloudy and viscous, which hinders filtration, decreases yield, and causes the loss of quality after its processing and during storage. This study aimed to evaluate enzymatic treatment effects using crude multi-enzymatic extracts (CME) obtained from Rhodotorula mucilaginosa, Rhodotorula orizycola, and Pseudozyma sp. produced by submerse fermentation in the extraction of juice guava. Mixtures of 100 ml of guava pulp and multi-enzymatic extracts proposed by Doehlert planning were incubated under constant agitation at 150 rpm and 50°C, and a Doehlert design was applied as a multivariate optimization strategy. The optimal conditions using the multi-enzymatic extract were: 0.4% (v/v) of CME for 131 min for the multi-enzymatic treatment using Pseudozyma sp.; 3.0% (v/v) of CME for 154 min using the R. mucilaginosa CME; and 5.0% (v/v) of CME for 90 min using R. oryzicola. The maximum viscosity reduction values for the juices treated with the CME of yeasts were 10.33%, 86.38%, and 13.33% for the juices treated with the CME of Pseudozyma sp., R. mucilaginosa, and R. orizycola, respectively. The physical-chemical properties were improved after treatment with CMEs, yielding a reduction of clarity, increase of total soluble solids and reducing sugars, and decreasing the acidity (pH) for all treatments with enzymatic extracts of all strains. The yeasts studied showed a potential for CME production to be applied to juice, improving the quality of the juice, and R. mucilaginosa was the most prominent yeast due to most significant reduction of viscosity in guava juice.

Assuntos

RESUMO

AIM: To identify and analyse genes that encode pectinases in the genome of the fungus Colletotrichum lindemuthianum, evaluate the expression of these genes, and compare putative pectinases found in C. lindemuthianum with pectinases produced by other fungi and oomycetes with different lifestyles. METHODS AND RESULTS: Genes encoding pectinases in the genome of C. lindemuthianum were identified and analysed. The expression of these genes was analysed. Pectinases from C. lindemuthianum were compared with pectinases from other fungi that have different lifestyles, and the pectinase activity in some of these fungi was quantified. Fifty-eight genes encoding pectinases were identified in C. lindemuthianum. At least six types of enzymes involved in pectin degradation were identified, with pectate lyases and polygalacturonases being the most abundant. Twenty-seven genes encoding pectinases were differentially expressed at some point in C. lindemuthianum during their interactions with their host. For each type of pectinase, there were at least three isoenzyme groups. The number of pectinases present in fungi with different lifestyles seemed to be related more to the lifestyle than to the taxonomic relationship between them. Only phytopathogenic fungi showed pectate lyase activity. CONCLUSIONS: The collective results demonstrate the pectinolytic arsenal of C. lindemuthianum, with many and diverse genes encoding pectinases more than that found in other phytopathogens, which suggests that at least part of these pectinases must be important for the pathogenicity of the fungus C. lindemuthianum. SIGNIFICANCE AND IMPACT OF THE STUDY: Knowledge of these pectinases could further the understanding of the importance of this broad pectinolytic arsenal in the common bean infection and could be exploited for biotechnological purposes.

Assuntos

RESUMO

Hydrogen sulfide (H2S) plays several physiological roles in plants. Despite the evidence, the role of H2S on cell wall disassembly and its implications on fleshy fruit firmness remains unknown. In this work, the effect of H2S treatment on the shelf-life, cell wall polymers and cell wall modifying-related gene expression of Chilean strawberry (Fragaria chiloensis) fruit was tested during postharvest storage. The treatment with H2S prolonged the shelf-life of fruit by an effect of optimal dose. Fruit treated with 0.2 mM H2S maintained significantly higher fruit firmness than non-treated fruit, reducing its decay and tripling its shelf-life. Additionally, H2S treatment delays pectin degradation throughout the storage period and significantly downregulated the expression of genes encoding for pectinases, such as polygalacturonase, pectate lyase, and expansin. This evidence suggests that H2S as a gasotransmitter prolongs the post-harvest shelf-life of the fruit and prevents its fast softening rate by a downregulation of the expression of key pectinase genes, which leads to a decreased pectin degradation.

Assuntos

RESUMO

Papaya is a fleshy fruit that undergoes fast ethylene-induced modifications. The fruit becomes edible, but the fast pulp softening is the main factor that limits the post-harvest period. Papaya fast pulp softening occurs due to cell wall disassembling coordinated by ethylene triggering that massively expresses pectinases. In this work, RNA-seq analysis of ethylene-treated and non-treated papayas enabled a wide transcriptome overview that indicated the role of ethylene during ripening at the gene expression level. Several families of transcription factors (AP2/ERF, NAC, and MADS-box) were differentially expressed. ACO, ACS, and SAM-Mtase genes were upregulated, indicating a high rate of ethylene biosynthesis after ethylene treatment. The correlation among gene expression and physiological data demonstrated ethylene treatment can indeed simulate ripening, and regulation of changes in fruit color, aroma, and flavor could be attributed to the coordinated expression of several related genes. Especially about pulp firmness, the identification of 157 expressed genes related to cell wall metabolism demonstrated that pulp softening is accomplished by a coordinated action of several different cell wall-related enzymes. The mechanism is different from other commercially important fruits, such as strawberry, tomato, kiwifruit, and apple. The observed behavior of this new transcriptomic data confirms ethylene triggering is the main event that elicits fast pulp softening in papayas.

Assuntos

RESUMO

In this review, we describe our experience in building a pilot-scale packed-bed solid-state fermentation (SSF) bioreactor, with provision for intermittent mixing, and the use of this bioreactor to produce pectinases and lipases by filamentous fungi. We show that, at pilot scale, special attention must be given to several aspects that are not usually problematic when one works with laboratory-scale SSF bioreactors. For example, it can be a challenge to produce large amounts of inoculum if the fungus does not sporulate well. Likewise, at larger scales, the air preparation system needs as much attention as the bioreactor itself. Sampling can also be problematic if one wishes to avoid disrupting the bed structure. In the fermentations carried out in the pilot bioreactor, when the substrate bed contained predominantly wheat bran, the bed shrank away from the walls, providing preferential flow paths for the air and necessitating agitation of the bed. These problems were avoided by using beds with approximately 50% of sugarcane bagasse. We also show how a mathematical model that describes heat and water transfer in the bed can be a useful tool in developing appropriate control schemes. Graphical Abstract.

Assuntos

RESUMO

BACKGROUND: Pectinase enzymes catalyze the breakdown of pectin, a key component of the plant cell wall. At industrial level, pectinases are used in diverse applications, especially in food-processing industry. Currently, most of the industrial pectinases have optimal activity at mesophilic temperatures. On the contrary, very little is known about the pectinolytic activities from organisms from cold climates such as Antarctica. In this work, 27 filamentous fungi isolated from marine sponges collected in King George Island, Antarctica, were screened as new source of cold-active pectinases. RESULTS: In semi-quantitative plate assays, 8 out 27 of these isolates showed pectinolytic activities at 15 °C and one of them, Geomyces sp. strain F09-T3-2, showed the highest production of pectinases in liquid medium containing pectin as sole carbon source. More interesting, Geomyces sp. F09-T3-2 showed optimal pectinolytic activity at 30 °C, 10 °C under the temperature of currently available commercial mesophilic pectinases. CONCLUSION: Filamentous fungi associated with Antarctic marine sponges are a promising source of pectinolytic activity. In particular, pectinases from Geomyces sp. F09-T3-2 may be potentially suitable for biotechnological applications needing cold-active pectinases. To the best of our knowledge, this is the first report describing the production of pectinolytic activity from filamentous fungi from any environment in Antarctica.

Assuntos

RESUMO

BACKGROUND: Pectinase enzymes catalyze the breakdown of pectin, a key component of the plant cell wall. At industrial level, pectinases are used in diverse applications, especially in food-processing industry. Currently, most of the industrial pectinases have optimal activity at mesophilic temperatures. On the contrary, very little is known about the pectinolytic activities from organisms from cold climates such as Antarctica. In this work, 27 filamentous fungi isolated from marine sponges collected in King George Island, Antarctica, were screened as new source of cold-active pectinases. RESULTS: In semi-quantitative plate assays, 8 out 27 of these isolates showed pectinolytic activities at 15 °C and one of them, Geomyces sp. strain F09-T3-2, showed the highest production of pectinases in liquid medium containing pectin as sole carbon source. More interesting, Geomyces sp. F09-T3-2 showed optimal pectinolytic activity at 30 °C, 10 °C under the temperature of currently available commercial mesophilic pectinases. CONCLUSION: Filamentous fungi associated with Antarctic marine sponges are a promising source of pectinolytic activity. In particular, pectinases from Geomyces sp. F09-T3-2 may be potentially suitable for biotechnological applications needing cold-active pectinases. To the best of our knowledge, this is the first report describing the production of pectinolytic activity from filamentous fungi from any environment in Antarctica.

Assuntos

RESUMO

Galactanases (endo-ß-1,4-galactanases-EC 3.2.1.89) catalyze the hydrolysis of ß-1,4 galactosidic bonds in arabinogalactan and galactan side chains found in type I rhamnogalacturan. The aim of this work was to understand the catalytic function, biophysical properties, and use of a recombinant GH53 endo-beta-1,4-galactanase for commercial cocktail supplementation. The nucleotide sequence of the endo-ß-1,4-galactanase from Bacillus licheniformis CBMAI 1609 (Bl1609Gal) was cloned and expressed in Escherichia coli, and the biochemical and biophysical properties of the enzyme were characterized. The optimum pH range and temperature of Bl1609Gal activity were 6.5-8 and 40 °C, respectively. Furthermore, Bl1609Gal showed remarkable pH stability, retaining more than 75 % activity even after 24 h of incubation at pH 4-10. The enzyme was thermostable, retaining nearly 100 % activity after 1-h incubation at pH 7.0 at 25-45 °C. The enzymatic efficiency (K cat /K m ) against potato galactan under optimum conditions was 241.2 s(-1) mg(-1) mL. Capillary zone electrophoresis demonstrated that the pattern of galactan hydrolysis by Bl1609Gal was consistent with that of endogalactanases. Supplementation of the commercial cocktail ACCELLERASE(®)1500 with recombinant Bl1609Gal increased hydrolysis of pretreated sugarcane bagasse by 25 %.

Assuntos

RESUMO

The effect of maceration process on the profile of phenolic compounds, organic acids composition and antioxidant activity of grape juices from new varieties of Vitis labrusca L. obtained in industrial scale was investigated. The extraction process presented a high yield without pressing the grapes. The use of a commercial pectinase resulted in an increase on extraction yield and procyanidins B1 and B2 concentrations and a decrease on turbidity and concentration of catechins. The combination of 60 °C and 3.0 mL 100 kg(-1) of enzyme resulted in the highest extraction of phenolic compounds, reducing the content of acetic acid. The juices presented high antioxidant activity, related to the great concentration of malvidin, cyanidin, catechin and caffeic, cinnamic and gallic acids. Among the bioactive compounds, the juices presented high concentration of procyanidin B1, caffeic acid and trans-resveratrol, with higher levels compared to those reported in the literature.

Assuntos

RESUMO

UNLABELLED: The influence of oenological factors on cold-active pectinases from 15 preselected indigenous yeasts belonging to Aureobasidium pullulans, Filobasidium capsuligenum, Rhodotorula dairenensis, Cryptococcus saitoi and Saccharomyces cerevisiae was investigated. Pectinolytic enzymes were constitutive or partially constitutive; and high glucose concentration (200 g l(-1) ) did not affect or increased pectinase production at 12°C and pH 3·5 (up to 113·9 U mg(-1) ) only in A. pullulans strains. SO2 (120 mg l(-1) ) slightly affected the growth of A. pullulans strains but did not affect pectinase production levels. Ethanol (15%) barely affected pectinase activity of A. pullulans strains but diminished relative activity to 12-79% of basidiomycetous yeasts. Moreover, non-Saccharomyces strains showed promising properties of oenological interest. This study demonstrates that cold-active pectinases from some A. pullulans strains were able to remain active at glucose, ethanol and SO2 concentrations usually found in vinification, and suggests their potential use as processing aids for low-temperature winemaking. SIGNIFICANCE AND IMPACT OF THE STUDY: Nowadays, there is increasing interest in low-temperature winemaking. Nevertheless, commercial oenological pectinases, produced by fungi, are rarely active at low temperatures. Cold-active pectinases that are stable under vinification conditions are needed. This study indicated that cold-active and acid-tolerant pectinases from non-Saccharomcyes yeasts were able to remain active at glucose, ethanol and SO2 concentrations usually found in winemaking. Furthermore, not only are these yeasts a source of cold-active pectinases, but the yeasts themselves are also potential adjunct cultures for oenology to produce these enzymes during cold-winemaking.

Assuntos

RESUMO

In this work the antiproliferative activity of pectic substances obtained by different extraction methods from defatted rapeseed cake was assessed on cancer cell lines. The process consisted of sequential treatment with alkalized water (pH∼8), EDTA (0.01 M), alkaline protease (Alkalase 2.4L) and a commercial pectinase preparation (Viscozyme L or Pectinex Ultra SP-L). Pectic extracts identification was performed using spectroscopy and chromatography techniques. FT-IR and HPLC-IR results suggest that the neutral pectic extracts produced would be arabinogalactans and ß-galactans. All the pectic substances extracted (acid and neutral) from RSC exhibited antiproliferative activity, being more effective on MCF-7 cells than Caco-2. The most effective pectic extract was obtained by Alkalase 2.4 L which killed over 80% of MCF-7 cells and 60% of Caco-2 cells. At less than 10 mg/mL pectic extracts enriched in neutral sugars also exhibited antiproliferative activity (50 and 40%, respectively), which was superior to the modified citric pectins activity at the same concentration for the breast cancer cell line (61.6% for MCF-7 and 49.9% for Caco-2 cells). These results show that the antiproliferative activity depends on both the type of pectin (acid or neutral) and the extraction procedure.

Assuntos

RESUMO

Endo-polygalacturonase (endo-PGase) activity determinations generally rely on viscosity changes or reducing sugar ends produced by this activity over polygalacturonic acid. Torres and coworkers [Enzyme Microb. Technol. 48 (2011) 123-128] showed that ruthenium red (RR) is useful for endo-PGase determination. In this article, we present a high-throughput liquid-based endo-PGase assay based on the RR method and compare it with the viscosity determination method. The reduced assay uses a small volume of enzyme solution, 40 µg of polygalacturonic acid, and 45 µg of RR for each sample determination. Furthermore, we obtained an interconversion factor for RR and viscosity activities.

Assuntos

RESUMO

Since enzymatic degradation is a mechanism or component of the aggressiveness of a pathogen, enzymatic activities from a Fusarium graminearum isolate obtained from infected wheat spikes of Argentina Pampa region were studied in order to understand the disease progression, tending to help disease control. In particular, the significance of the study of polygalacturonase activity is based on that such activity is produced in the early stages of infection on the host, suggesting a crucial role in the establishment of disease. In this sense, polygalacturonase activity produced by this microorganism has been purified 375 times from 2-day-old culture filtrates by gel filtration and ion-exchange chromatography successively. The purified sample showed two protein bands in sodium dodecyl sulfate-polyacrylamide gels, with a molecular mass of 40 and 55 kDa. The protein bands were identified as an endopolygalacturonase and as a serine carboxypeptidase of F. graminearum, respectively, by peptide mass fingerprinting (matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF/TOF) fragment ion analysis). The pattern of substrate degradation analyzed by thin layer chromatography confirmed the mode of action of the enzyme as an endopolygalacturonase. High activity of the polygalacturonase against polygalacturonic acid was observed between 4 and 6 of pH, and between 30 and 50 °C, being 5 and 50 °C the optimum pH and temperature, respectively. The enzyme was fully stable at pH 5 for 120 min and 30 °C and sensible to the presence of some metal ions. This information would contribute to understand the most favorable environmental conditions for establishment of the disease.

Assuntos

RESUMO

Objetivo. Determinar actividades amilolíticas, celulolíticas, lipolíticas, pectinolíticas y proteolíticas en 32 aislamientos de Fusarium spp. de origen humano, animal y vegetal. Materiales y métodos. Las actividades enzimáticas se determinaron a nivel cualitativo, por medio de la medición de halos de hidrólisis en placas de agar con el respectivo sustrato, y a nivel cuantitativo se realizó un cultivo líquido para determinar la degradación del respectivo sustrato por medio de técnicas colorimétricas. Resultados. Todos los aislamientos presentaron actividades enzimáticas a nivel cualitativo, excepto las amilolíticas y lipolíticas. La determinación a nivel cuantitativo fue posible para las enzimas evaluadas, a excepción de las lipasas. Conclusión. La determinación de los perfiles enzimáticos amilolíticos, celulolíticos, pectinolíticos y proteolíticos de cada uno de los aislamientos evaluados pertenecientes al género Fusarium sugirió su capacidad, indistintamente de su procedencia, de degradar estos sustratos...

Assessment of enzymatic characterization of Fusarium spp. isolated from human, animal, and plant wounds. Objective. To determine amylolytic, cellulolytic, lipolytic, pectinolytic and proteolytic activities in 32 Fusarium spp. isolates from humans, animals and plants. Materials and methods. Qualitative determination of enzymatic activities was done by measuring hydrolysis halos in agar plates with their corresponding substrate. Quantitative determination was done by colorimetric techniques, using liquid culture supernatants to determine the respective substrate degradation. Results. All isolates showed enzymatic activities from a qualitative point of view, except amylolytic and lipolytic. Quantitative determination was possible for all the evaluated enzymes except lipases. Conclusion. The determination of amylolytic, cellulolytic, pectinolytic and proteolytic enzymatic profiles of each of the Fusarium isolates assessed suggests their capacity to degrade these substrates, irrespectively of their origin...

Avaliação das atividades enzimáticas de Fusarium spp. Isolados a partir de lesões em humanos, animais e plantas. Objetivo. Determinar as atividades amilolíticas, celulolíticas, lipolítica, pectinolíticas e proteolíticas em 32 isolamentos de Fusarium spp. de origem humana, animal e vegetal. Materiais e métodos. As atividades enzimáticas foram determinadas a nível qualitativo medindo os halos de hidrólise em placas de agar com o substrato respectivo e a nível quantitativo realizou-se uma cultura líquida para determinar a degradação do substrato respectivos por meio de técnicas colorimétricas. Resultados. Todos os isolados apresentaram uma atividade enzimática a nível qualitativo, exceto as amilolíticas e lipolíticas. A determinação a nível quantitativo foi possível para as enzimas testadas, exceto para as lipases. Conclusão. A determinação de perfis enzimáticos amilolíticos, celulolíticos, pectinolíticos e proteolíticos de cada um dos isolados testados pertencentes ao gênero Fusarium, sugeriu sua capacidade, independentemente da sua origem, para degradar estes substratos...

Assuntos

RESUMO

Fusarium graminearum isolates from three different agroecological regions in Argentina were examined according to the production of different extracellular enzyme activities of potential biotechnological interest: pectinases (PGase: polygalacturonase and PMGase: polymethylgalacturonase), cellulase (CMCase: carboxymethylcellulase) and hemicellulase (xylanase). The isolates were grown in minimum salt medium supplemented with 0.25 percent glucose, 0.125 percent citric pectin and 0.125 percent oat bran as carbon sources and/or enzyme inducers. PGase activity was detected early (after two days of incubation) in all the cultures; it was found to be the highest for all the isolates. PMGase was high only for those isolates of the II region. CMCase and endoxylanase activities were particularly found at late stages (after four and seven days of incubation, respectively) and the maximum values were lower than pectinase activities.

RESUMO

Response surface methodology was used for optimization of polygalacturonase (PG) and pectinesterase (PE) production in submerged fermentation by A.niger. A Central Composite Experimental Design was applied, consisting of 22 experiments, including eight central points. Variables studied were: fermentation time (24 to 120 h), pH (3.5 to 6.5) and initial concentration of pectin (5 to 20 g/l). Maximum PE production was 220 U/l, after 74 h of culture, in a medium containing 20 g/l of pectin (pH 6.5). The optimal conditions for PG production were pH: 4.1, 20 g/l of pectin and 94 h of fermentation with a maximum value of 1032 U/l. Under these conditions, the PE production was low (15 U/l). A liquid extract with high PG activity and low PE activity could be suitable to be used in food processing in order to reduce the production of methanol.

A metodologia de superfície de resposta foi utilizada para a otimização da produção de poligalacturonasa (PG) e pectinesterasa (PE), por A. niger em fermentação submergida. Foi aplicado um Desenho Experimental Composto Central abrangendo 22 experiências, incluindo oito pontos centrais. As variáveis estudadas foram: tempo de fermentação (24 a 120 h), pH (3.5 a 6.5) e concentração inicial de pectina (5 a 20 g/l). A produção máxima de PE foi de 220 U/l, após 74h de cultivo, 20 g/l de pectina e pH 6.5. As condições ótimas para a produção de PG foram pH 4.1, 20 g/l de pectina e 94 h de fermentação, com um valor máximo de 1032 U/l. Sob estas condições, a produção de PE foi baixa (15 U/l). Um extrato líquido com alta atividade PG e baixa atividade PE poderia ser conveniente para ser utilizado no processamento e alimentos, visando reduzir a produção de metanol.

RESUMO

Protoplast fusion between complementary auxotrophic and morphological mutant strains of Penicillium griseoroseum and P. expansum was induced by polyethylene glycol and calcium ions (Ca2+). Fusant strains were obtained in minimal medium and a prototrophic strain, possibly diploid, was chosen for haplodization with the fungicide benomyl. Different recombinant strains were isolated and characterized for occurrence of auxotrophic mutations and pectinolytic enzyme production. The fusant prototrophic did not present higher pectinase production than the parental strains, but among 29 recombinants analyzed, four presented enhanced enzyme activities. The recombinant RGE27, which possesses the same auxotrophic and morphologic mutations as the P. griseoroseum parental strain, presented a considerable increase in polygalacturonase (3-fold) and pectin lyase production (1.2-fold).

Fusões de protoplastos entre linhagens mutantes auxotróficas e morfológicas complementares de Penicillium griseoroseum e P. expansum foram induzidas por polietilenoglicol e íons cálcio (Ca2+). Fusionantes foram obtidos em meio mínimo e uma linhagem prototrófica, possivelmente diplóide, foi selecionada para a haploidização com o fungicida benomil. Diferentes linhagens recombinantes foram isoladas e caracterizadas quanto à presença de mutações auxotróficas e a produção de enzimas pectinolíticas. O fusionante prototrófico não apresentou maior atividade de pectinases em relação às linhagens parentais, entretanto, entre 29 recombinantes analisados, quatro apresentaram maiores atividades enzimáticas. O recombinante RGE27, o qual possui as mesmas mutações auxotróficas e morfológicas que a linhagem parental de P. griseoroseum, apresentou um aumento considerável na produção de poligalacturonase (3 vezes) e de pectina liase (1,2 vezes).

RESUMO

Uma pectinase foi usada em um ensaio de clarificação de um fermentado alcoólico de caldo de laranja. Em mosto fermentado que não clarificou totalmente depois das trasfegas, a adição de pectinase causou rápida clarificação, não prejudicou as características organolépticas do produto final e contribuiu para aumentar o rendimento da bebida, separando-a das borras em quantidade expressiva, sem afetar o buquê.(AU)

Pectinase was used in a test of clarification of a fermented orange juice. The enzyme contributed to reduce the time of clarification and to increase the sedimentation of the colloidal constituents of the fermented juice. The enzyme in small amounts contributed to reduce the time of clarifícation and to increase the yield of the fruit wine, recovering ii in an expressively amount from the sedimented colloids without loss of flavour properties. (AU)

Assuntos

RESUMO

Penicillium griseoroseum was grown in bioreactors on mineral medium supplemented with yeast extract and sucrose. The influence of inoculum and carbon source concentrations, aeration and pH on pectin lyase (PL) production, as well as the capacity of P. griseoroseum to produce PL when grown on sugar cane syrup as carbon source were evaluated. Inoculum concentration did not influence PL production. Production was higher in non-aerated than in aerated medium. The best results were obtained using 60 mM sucrose at pH 6.3-7.2. Production using cane syrup 25% (v/v), without yeast extract supplement, was equal to that obtained under the conditions cited above.

Penicillium griseoroseum foi cultivado em biorreatores em meio mineral suplementado com extrato de levedura e sacarose. As influências das concentrações do inóculo e da fonte de carbono, da aeração e do pH do meio de cultivo sobre a produção de pectina liase (PL), bem como a capacidade de P. griseoroseum em produzir PL quando cultivado em caldo de cana diluído foram avaliadas. A concentração do inóculo não influenciou significativamente a produção de PL. O cultivo do fungo em biorreatores não aerados favoreceu a produção da PL em detrimento aos biorreatores com injeção de ar. Maior produção de PL foi obtida com o cultivo de P. griseoroseum em meio com pH 6,3 - 7,2, adicionado de 60 mM de sacarose. Quando cultivado em caldo de cana diluído, 25% (v/v), sem suplementação com extrato de levedura, a atividade máxima de PL alcançada foi igual as das condições citadas acima.