Production Of Pectinolytic Enzymes Research Articles

The Gpmk1 MAP kinase of Fusarium graminearum regulates the induction of specific secreted enzymes

Recently, we described Gpmk1 MAP kinase-disruption mutants of Fusarium graminearum that were fully viable in vitro, but had completely lost their ability to infect wheat. As cell wall-degrading enzymes are postulated to participate in the infection process of F. graminearum, these MAP kinase-disruption mutants were analysed for their ability to produce cell wall-degrading enzymes in vitro and compared with the wild-type strain. The gpmk1 disruption had no effect on the production of pectinolytic or amylolytic enzymes. However, Gpmk1 regulates the early induction of extracellular endoglucanase, xylanolytic, and proteolytic activities. Furthermore, the MAP kinase was responsible for the overall induction of secreted lipolytic activities. Since the disruption of the Gpmk1 MAP kinase leads to an apathogenic phenotype, these results suggest that the infection process of F. graminearum depends on the secretion of cell wall-degrading enzymes, particularly during the early infection stage. Finally, this work provides the first detailed analysis of the apathogenic phenotype of the F. graminearum Gpmk1 mutants.

Studies on the utilization of citrus peel for pectinase production using fungus Aspergillus niger

The fruit processing industries produce a large amount of waste material, which poses considerable disposal problems and ultimately leads to pollution. In the processing of citrus fruits, a large proportion of the produce goes waste in the form of peel, pulp and seeds. Dried citrus peel is rich in carbohydrates, proteins and pectin; pectin acts as the inducer for production of pectinolytic enzymes by microbial systems. Thus, in the present study, dried citrus peel was used as substrate for the production of pectinase (Endopolygalacturonase; EC 3.2.1.15) by fungus Aspergillus niger. Maximum enzyme activity was obtained with 15% substrate, which gives a semi‐solid mass, when incubated at 30°C for 120 h.

Screening and genetic improvement of pectinolytic fungi for degumming of textile fibers

Aiming at contributing to technological improvements in plant fiber processing methods, this paper reports research work on the obtainment of more efficient pectinase-producing fungi strains. More specifically, this work reports the analysis of 18 strains of filamentous fungi, with the purpose of obtaining enzymes for textile fibers degumming. The strains were evaluated for production of pectinolytic enzymes under several growth conditions (culture medium and growth temperature). Production of pectinases was measured by an enzymatic index (EI) in solid pectin medium. Among the tested strains, Penicillium chrysogenum IFO 4626 (Q 176) showed the best performance. Genetic improvement of this strain was carried out to increase its pectinase production, while keeping cellulase activity down to a negligible level, since cellulases are known to decrease the resistance of the fiber. Variability was induced through several cycles of mutation and selection by exposing conidea to ultra-violet light (UV). We selected 39 out of 390 isolated colonies. Resulting mutants produced nine times more pectin lyase (PL) than the original strain in terms of PL specific activity, and five times more in terms of PL activity (i.e. mmoles liberated per minute of reaction per mL of medium). Periodically, mutant performance was evaluated in solid pectin medium. Genetic stability was maintained for four years after isolation.

Pectinolytic enzyme production by Bacillus species and their potential application on juice extraction

Five Bacillus strains isolated from decaying vegetable material were cultivated on wheat bran and endo-polygalacturonases, exo-polygalacturonase and pectin lyase activities in the crude enzymatic solution obtained were determined. Highest activity was observed for all enzymes when fermentation was carried out at 28 °C, the highest activity values were obtained after 120 h of cultivation for exo-PG and after 48 h for endo-PG and PL. The use of the enzymatic solution for treatment of fruits and vegetable mash afforded a high juice extraction and a pulp with good pressing characteristics.

Influence of heavy metals on production and activity of pectinolytic enzymes in ericoid mycorrhizal fungi

Ericoid mycorrhizal fungi increase the ability of their host plants to colonise soils polluted with heavy metal ions, although the mechanisms are not clearly understood. Two mycorrhizal mycelia of Oidiodendron maius isolated from contaminated soil were previously shown to tolerate high concentrations of heavy metal ions in the growth medium. The influence of zinc ions on the secretion and activity of polygalacturonase (PG), an extracellular enzyme that hydrolyses the pectin component of the plant cell walls, was investigated because of their significance during saprotrophic growth. Two major PG isoforms expressed both in the absence and in the presence of increasing concentrations of zinc ions were identified. The PG isoforms were purified from the tolerant Oidiodendron strains as well as from ericoid fungal isolates from non-polluted soils. Addition of increasing concentrations of Zn and Cd ions to the purified enzymes resulted in an increase of PG activity of both tolerant and non tolerant O. maius isolates at doses below 1 mM. By contrast, at the same metal ion concentrations PG activity of a sterile isolate from non-polluted soil was unaffected or slightly inhibited. We speculate that the response of PG to heavy metal ions may have been a pre-adaptive factor for the colonisation of polluted soils by O. maius.

Production of xylanases, mannanases, and pectinases by the thermophilic fungus Thermomyces lanuginosus

A group of 17 strains of the thermophilic fungus Thermomyces lanuginosus was examined for the production of xylanases, β-mannanases, arabinanases, and pectinases. All strains were found to be xylanolytic, and several were proven to be outstanding producers of microbial xylanase on glucuronoxylan and corn cobs. The strains hyperproducing xylanase secreted low amounts of xylan-debranching enzymes and did not produce β-mannan and arabinan-degrading enzyme systems. Only the strains showing lower xylanase production exhibited a higher degree of xylan utilization and also the ability to produce a mannanolytic enzyme system. One of the mannanolytic strains was found to be capable of producing arabinan-degrading enzymes. This strain also showed the best production of pectinolytic enzymes during growth on citrus pectin or sugar beet pulp. Some of the strains have good potential for use as sources of important industrial enzymes of high thermal stability.

Short Note: Production and properties of pectinolytic enzymes from the thermophilic fungus, Thermomyces lanuginosus

Maximal pectinolytic activity was detected in the culture filtrates of Thermomyces lanuginosus when grown in medium containing pectin and sucrose. The pectinolytic enzyme system was optimally active at pH 5.5 and at 70°C with potassium pectate and at pH 4.5 at 50°C with pectin as substrates. Zymogram analyses showed two activity bands with pectin and three with potassium pectate.

Culture conditions for the production of pectinolytic enzymes by the white‐rot fungus Trametes trogii on a laboratory scale

AbstractDifferent cultural parameters that regulate pectinolytic enzyme production in vitro by Trametes trogii were studied. When grown in a medium containing pectin, T. trogii produced extracellular polymethylgalacturonase, polygalacturonase and pectin lyase but no pectate lyase activity. No significant differences in the maximum enzyme activities measured were observed with the addition of xylan, carboxymethylcellulose or both to the medium containing pectin. The addition of glucose to that medium considerably decreases all the activities studied, and in a medium with glucose as the sole carbon source no galacturonase activity could be measured, and pectin lyase activity was at its minimum. The low synthesis of pectin lyase in cultures containing glucose suggests that this enzyme is constitutive in contrast to the polygalacturonases that were not detected. The increase in pectin concentration stimulated growth and enzyme production. The highest specific activities were attained with the greatest concentration tested (15 g/l). Casamino acids were the best nitrogen source for enzyme production. Maximum growth was measured at pH 3.3; pH values of around 4.5 stimulated enzyme production, but high pectinase activities were also detected in media with more alkaline initial pH values (6.2 for galacturonases and 6.6 for lyases), probably owing to the specific induction of particular isoforms. In the range of 23 to 28°C, good results were obtained in growth as well as in enzyme production. The addition of Tween 80 promoted growth and gave the highest yield of polymethylgalacturonase and pectin lyase (0.37 and 36.2 E.U./ml, respectively). The highest polygalacturonase activity (1.1 E.U/ml) was achieved with polyethylene glycol. Tween 20 and Triton X‐100 inhibited growth and pectinase production.

Some Pectinolytic and Cellulolytic Enzyme Activities of Fungi Causing Rots of Cocoyams

Representative isolates of Aspergillus niger, Botryodiplodia theobromae, Corticium rolfsii, Geotrichum candidum, Fusarium oxysporum and F solani recovered from rotten cocoyams were studied for the production of pectinolytic and cellulolytic enzymes. All the isolates elaborated high levels of hydrolase, lyase and pectinesterase in cocoyam tissue medium and lyase and pectinesterase in pectin medium. There were no significant differences in the overall levels of lyase and pectinesterase activities produced by all the isolates in both media. The level of hydrolase, lyase and pectinesterase activities individually produced by A niger, B theobromae and C rolfsii in both media was significantly higher than that of any other isolate. The highest hydrolase activity was produced by C rolfsii in cocoyam medium while A niger produced the highest lyase activity in pectin medium. Maximum pectinesterase activity was obtained from B theobromae and C rolfsii in pectin medium. All the test isolates produced cellulase in a medium containing carboxymethyl cellulose with C rolfsii showing significantly high activity followed by F oxysporum and A niger. © 1997 SCI.

Aggressiveness and production of cell-wall degrading enzymes by Pythium violae, Pythium sulcatum and Pythium ultimum, responsible for cavity spot on carrots

This study investigated the relationships between pathogenesis, types of symptoms and in vitro production of cell-wall degrading enzymes by P. violae, P. sulcatum and P. ultimum. The three pathogens, considered as the three Pythium species principally responsible for cavity spot on carrot roots, secreted only low levels of fatty acid esterases activity, suggesting they have limited ability to degrade suberin in the walls of the outer cell layers of carrot tissues. Among the enzymes that degrade cell-wall polysaccharides, only pectate lyases and cellulases were produced by P. violae, and these were produced late and in small amounts: the symptoms caused by P. violae were limited and typical of cavity spot. Conversely, P. ultimum caused maceration of tissues, and secreted polygalacturonases and β-1,4-glucanases earlier and in larger amounts than P. violae. P. ultimum also produced a large diversity of proteins and cellulase isoenzymes. Although secreting all the monitored enzymes in higher quantity than the two previous species, P. sulcatum was responsible for only typical limited symptoms of cavity spot, with a brown colouring. The role of plant reactions induced in response to early pectinolytic enzyme production by P. sulcatum may account for this apparent inconsistency.

Protoplasts from pectinolytic fungi: isolation, regeneration and pectinolytic enzyme production

S. Solis, M.E. FLORES AND C. HUITRON. 1996. Protoplast release in pectinolytic strain mutants of Aspergillus sp. CH-Y-1043 (A13) and Aspergillus flavipes ATCC-16795 (F7) is described. Optimum yield of protoplasts A13 was obtained in a lapse of 1 h when commercially lytic enzymes of Trichoderma harzanium (2 mg ml−1) were added in 0.05 mol 1−1 citrate-phosphate buffer pH 5.0 containing 0.7 mol 1−1 KCl and 10 mg ml−1 BSA. Best results in F7 were obtained when the protoplasting system of A13 was supplemented with 10 mg ml−1Aureobasidium sp. lytic enzymes. Isolated protoplasts in A13 and F7 were capable of a high regeneration frequency of 87% and 53% when 0.7 mol 1−1 KCl and sorbitol were used as osmotic stabilizers. Endo-P, Exo-P and pectin lyase production were not modified during the process of regeneration.

Regulation by Galacturonic Acid of Pectinolytic Enzyme Production by Sclerotinia sclerotiorum

Production of polygalacturonases and pectinases from Sclerotinia sclerotiorum was induced in vitro by galacturonic acid. The inductive effect of galacturonic acid was abolished by the presence of glucose, leading to a basal enzyme production. Zymograms of extracellular enzymes showed that galacturonic acid induced the synthesis of six polygalacturonase and one pectin-methylesterase isoforms. Immunoblotting revealed that an exo-polygalacturonase and an exo-polymethylgalacturonase were secreted in all conditions. They are not glucose repressed and not regulated by galacturonic acid. These constitutive enzymes provide the pathogen with the inherent ability to release galacturonic acid from plant cell walls and to trigger inducible enzyme synthesis.

Effect of inorganic phosphate on the secretion of pectinolytic enzymes byAspergillus niger

Inorganic phosphates, taken as NaH2PO4 or KH2PO4, stimulated the production of pectinolytic enzymes and enhanced by up to two-fold the growth of Aspergillus niger in submerged liquid culture of apple pomace. Production of extracellular enzymes of endo- and exo- types, showed a different response to concentrations of phosphate in the medium.

EFFECT OF GRADED LEVELS OF POTASSIUM ON PECTINOLYTIC AND CELLULOLYTIC ENZYMES IN BLAST INFECTED LEAVES OF RICE

The effect of increasing doses of potassium against Pyricularia oryzae inoculation on the production of pectinolytic and cellulolytic enzymes in inoculated leaves was studied in rice variety IR..50. The activity of protopectinase (PP), polygalacturonase (PG), poly galacturonate trans eliminase (PGTE), Pectin trans eliminase (PTE) and cellulases (C1 and Cx) was found to decline due to higher levels of potassium. On the other hand, B glucosidase activity was enhanced markedly as the rate of potassium application increased. The increased ẞ-glucosidase activity due to increased application of potassium inhibited the lesion development, thereby resisting the entry of the pathogen into the host.

Influence of Carbendazim Concentration on in Vitro Production of Pectinolytic and Cellulolytic Enzymes By Rhizoctonia solani

Influence of Carbendazim Concentration on in Vitro Production of Pectinolytic and Cellulolytic Enzymes By Rhizoctonia solani

Isolation of Erwinia chrysanthemi mutants altered in pectinolytic enzyme production.

Various mutations in the pectin catabolic pathway of Erwinia chrysanthemi were isolated by selection of Mu-lac insertions, resulting in expression of the lac genes inducible by pectin degradation products. This approach allowed us to isolate lacZ fusions with the genes pelC, pelD, ogl and pem, encoding pectate lyases PLc and PLd, oligogalacturonate lyase and pectin methylesterase, respectively. Moreover, we obtained mutations affecting the regulation of pectinolytic enzymes; a locus called pecl appeared to be involved in induction of pectate lyases and pectin methylesterase. A second locus, called pecL, may encode an activator protein acting on pectate lyase production. Both pecl and pecL expression are induced in the presence of pectic polymers. The expression of the pem gene was studied in more detail by analysis of the pem-lacZ fusions. The expression of pem appears to be controlled by the negative regulatory gene kdgR, which controls all the genes involved in pectin degradation (pem, pel, ogl, kduD, kdul, kdgK, kdgA). This study confirmed that 2-keto-3-deoxygluconate is a key intermediate for the induction of the pectin catabolic pathway. The three genes pem, pelD and pecl were localized in the same region, near the ade-377 marker on the genetic map of the E. chrysanthemi strain 3937. The pem gene was located more precisely on an 18kb DNA fragment containing the pelADE cluster. However, this 18kb DNA fragment did not complement the pecl mutation. The pecL mutations were located near the ile-2 marker on the genetic map of E. chrysanthemi strain 3937.

Influence of the mycelium growth conditions on the production of amylolytic, proteolytic and pectinolytic enzymes by Aspergillus niger C

AbstractVarious nitrogen and carbon sources, as well as natural products, were examined as inducers of the production of amylases, proteases and pectinases by A. niger C. A. niger C grown on wheat bran extract medium provided culture supernatants with the highest enzymatic activities. Some culture conditions, e.g. pH, medium temperature and time period of cultivation, were optimalized to improve the growth and enzymes biosynthesis by A. niger C.

Some extracellular enzymes associated with two tomato fruit spoilage molds

The production of amylolytic, cellulolytic and pectinolytic enzymes by Aspergillus flavus and A. fumigatus was investigated. The two fungi were cultured on wheat offal and liquid crystalline carboxymethylcellulose media. A. flavus produced amylases on basal and starch containing media while A. fumigatus could only produce amylases on starch medium. The cellulolytic activities of filtrates from culture or infected fruits showed that A. flavus produced lesser quantities of cellulolytic enzymes than A. fumigatus. At 25 °C and at a pH range of 6–8, A. flavus best produces amylases and cellulases, while A. fumigatus showed highest activities of the two enzymes at 35–40 °C and at pH 7.0. Two pectinolytic enzymes — polymethylgalacturonase and pectinmethyltrans-eliminase — were identified in vivo with the two molds. An endopolygalacturonase in addition to these two pectinolytic enzymes was well associated with A. fumigatus.

Influence of Fungicides on the Production of Pectinolytic Enzymes of R. solani

Influence of Fungicides on the Production of Pectinolytic Enzymes of R. solani

Production of pectinolytic enzymes by Colletotrichum capsici (Syd.) Butler and Bisby.

Colletotrichum capsici produced protopectinase, polygalacturonase and polymethylesterase. Polymethylesterase removed 2.42 mg of methoxyl per ml of culture filtrate in 3 hrs.