A chemically-defined medium for production of compactin by Penicillium citrinum

A mutant strain of Penicillium citrinum grown in a chemically-defined production medium, yielded 145 mg compactin l^–1. The medium also facilitated spectrophotometric analysis of compactin. Addition of KH₂PO₄in the production medium did not increase the compactin production, while addition of a surfactant, Tween 80, increased compactin to 175 mg l^–1. Inoculation with 10⁷ spores ml^–1 and initial pH of 6.5–7 were the most suitable for compactin production.     

Cloning of the cellulase gene from Penicillium funiculosum and its expression in Escherichia coli

A gene of Penicillium funiculosum encoding an endoglucanase was cloned and expressed in Escherichia coli using the lacZ promoter of vector pUC 18. The gene product hydrolyzed carboxymethyl cellulose and showed strong cross reactivity with P. funiculosum anticellulases.     

The effects of Penicillium digitatum and Fusarium oxysporum rots on nutritional content of pawpaw (Carica papaya L.)

Investigations were carried out on the effects of Penicillium digitatum and Fusarium oxysporum on the nutritional value of pawpaw (Carica papaya). Decreases were observed in ash content, phosphorus, sodium, reducing sugars and ascorbic acid levels of fruits infected with P. digitatum, but increases in calcium and potassium content. In fruits infected by F. oxysporium, there were decreases in phosphorus, calcium, sodium ascorbic acid and reducing sugar levels; but the levels of ash content increased. The total protein level increased in the fruits infected with both fungi. These results revealed a reduction in fruit quality.     

Mass culture experiments with Brachionus Rubens

In order to develop the optimum conditions for a mass culture of Brachionus rubens, eight strains of phytoplankton were tested as food for the rotifers. The optimum food concentration as well as the concentration of algal medium tolerated by R. rubens, and the influence of nitrite, sodium chloride, extreme pH-values and low oxygen concentrations on the reproduction of B. rubens were determined.     

Response of severed Penicillium chrysogenum hyphae following rapid Woronin body plugging of septal pores

Colonies of Penicillium chrysogenum (Thom) Wisconsin strain Q176 were fixed at varying time intervals after having been severed with a razor blade and were examined by transmission electron microscopy. Within such colonies Woronin bodies were found to have plugged septal pores on either side of the cut, both towards and away from the hyphal apices. A very close association of Woronin bodies with septa was retained in damaged compartments emptied of virtually all other contents. In colonies fixed 3 h after cutting, deposition of material over the plugged pores occurred on the side of the septum away from the cut. The newly deposited material was similar in appearance to hyphal wall and septal plate constituents. This consolidation of the seal was apparently completed within 3 h because no further change was observed in colonies fixed 17 h after cutting.     

Effect of calcium on synthesis of dipicolinic acid inPenicillium citreoviride and its feedback resistant mutant

Dipicolinic acid synthesis inPenicillium citreoviride strain 3114 was inhibited by Ca²⁺ ions, but not by Ba²⁺, Cu²⁺or Fe²⁺. Among the metals tested, only Zn²⁺ inhibited the synthesis of dipicolinic acid and promoted sporulation. None of these metals reversed the inhibition by Ca²⁺ or Zn²⁺. A mutant 27133-dpa-ca selected for resistance to feedback inhibition by dipicolinic acid: Ca²⁺ complex showed cross-resistance to inhibition by dipicolinic acid: Zn²⁺. Both 3114 and271 33-dpa-ca excreted a number of aliphatic and amino acids during secondary metabolism of dipicolinic acid. In the presence of 1000 ppm of Ca²⁺, accumulation of citric acid and α-aminoadipic acid was completely inhibited under conditions of inhibition of dipicolinic acid in parent strain 3114 but not in the mutant. Citric acid with or without Ca²⁺ did not inhibit thede novo synthesis of dipicolinic acid in the strain 3114. In fact, citric acid in the presence of Ca²⁺ improved significantly rate of dipicolinic acid synthesis. Apart from resistance to feed back inhibition by dipicolinic acid: Ca²⁺ complex, mutant differed from the parent in three other aspectsviz. (i) dipicolinic acid synthesis was not subject to catabolite repression by glucose, (ii) sporulation as well as dipicolinic acid synthesis was dependent on the presence of Ca²⁺ ions in the medium and (iii) Mg²⁺ requirement for the mutant increased three fold. Higher requirement of the Mg²⁺ could be partially relieved by Ca²⁺ during secondary metabolism. The results support the inference thatde novo synthesis of dipicolinic acid is regulated through feedback inhibition by dipicolinic acid: Ca²⁺complex.     

Production of cellulases and hemicellulases by Penicillium echinulatum grown on pretreated sugar cane bagasse and wheat bran in solid-state fermentation

AIM: To evaluate the solid-state fermentation (SSF) production of cellulase and hemicellulases (xylanases), by Penicillium echinulatum 9A02S1, in experiments carried out with different concentrations of the pretreated sugar cane bagasse (PSCB) and wheat bran (WB). METHODS AND RESULTS: This study reports the production of xylanolytic and cellulolytic enzymes by P. echinulatum 9A02S1 using a cheap medium containing PSCB and WB under SSF. The highest amounts of filter paper activity (FPA) could be measured on mixtures of PSCB and WB (32.89 +/- 1.90 U gdm(-1)). The highest beta-glucosidase activity was 58.95 +/- 2.58 U gdm(-1) on the fourth day. The highest activity for endoglucanases was 282.36 +/- 1.23 U gdm(-1) on the fourth day, and for xylanases the activity was around 10 U gdm(-1) from the second to the fourth day. CONCLUSIONS: The present work has established the potential of P. echinulatum for FPA, endoglucanase, beta-glucosidase and xylanase productions in SSF, indicating that WB may be partially substituted by PSCB. SIGNIFICANCE AND IMPACT OF THE STUDY: The incorporation of cheap sources, such as sugar cane bagasse, into media for the production of lignocellulose enzymes should help decrease the production costs of enzymatic complexes that can hydrolyse lignocellulose residues for the formation of fermented syrups, thus contributing to the economic production of bioethanol.     

Three new species of penicillium

Three new species of microfungi belonging to the genus Penicillium Link ex Fries are described and illustrated. All but one have been isolated from the atmosphere of las Palmas, capital city of the island of Gran Canaria (Canary Islands, Spain). They clearly differ from all species of the genus described so far and are, therefore, described and proposed as new species: Penicillium hispanicum sp. nov., Penicillium grancanariae sp. nov., and Penicillium palmensis sp. nov.     

Polyol accumulation by two filamentous fungi grown at different concentrations of NaCl

The accumulation of polyols by Aspergillus niger (van Tiegh) strain S 1 and Penicillium chrysogenum (Thom) strain S 30 was followed during growth in media of different concentrations of NaCl. The major polyols found were glycerol, erythritol and mannitol. The total polyol pool increased in both organisms in response to raised salinity, and the proportion of glycerol and erythritol was markedly enhanced at high salinity.     

Initial steps of phloroglucinol metabolism in Penicillium simplicissimum

The pathway for the aerobic catabolism of 1,3,5-trihydroxybenzene (phloroglucinol) by a new strain of Penicillium was investigated using both in vivo and in vitro cell-free systems. The fungal strain was isolated by enrichment on phloroglucinol and identified as P. simplicissimum (Oud) Thom. It grew optimally at pH 5.5 and 27°C with 119 mM (1.5%w/v) of phloroglucinol in a basal mineral salts medium. Vapours of the crystalline substrate placed in a Petri-plate lid supported the growth of the fungal colonies on the agar surface. Mycelia grown on phloroglucinol accumulated 1,2,4-trihydroxybenzene and resorcinol in the medium. Washed, resting mycelia grown on phloroglucinol, when resuspended in a buffer utilized oxygen in the presence of catechol, resorcinol, pyrogallol and phloroglucinol. A NADPH-dependent reductase in the cell-free extract reduced phloroglucinol to dihydrophloroglucinol. This electron donor could not be replaced by NADH. Resorcinol hydroxylase, phloroglucinol reductase, catechol-1,2-oxygenase, and catechol-2,3-oxygenase were detected in cell-free extracts of mycelia grown on phloroglucinol. The possible steps in the degradation of phloroglucinol are discussed.