Jan Fiedurek

Terpenes: substances useful in human healthcare

Terpenes are naturally occurring substances produced by a wide variety of plants and animals. A broad range of the biological properties of terpenoids is described, including cancer chemopreventive effects, antimicrobial, antifungal, antiviral, antihyperglycemic, anti-inflammatory, and antiparasitic activities. Terpenes are also presented as skin penetration enhancers and agents involved in the prevention and therapy of several inflammatory diseases. Moreover, a potential mechanism of their action against pathogens and their influence on skin permeability are discussed. The major conclusion is that larger-scale use of terpenoids in modern medicine should be taken into consideration.

Technology for conversion of lignocellulosic biomass to ethanol

Abstract Current trends in production of fuel ethanol from lignocellulosic materials are reviewed. Particular emphasis has been laid on the microbial synthesis of cellulases, enzymatic hydrolysis, pretreatment of lignocellulosics, and their simultaneous saccharification and fermentation to ethyl alcohol. Some pilot-scale plants producing alcohol from biomass are also presented.

Screening and mutagenesis of moulds for the improvement of glucose oxidase production

Abstract The strain of Aspergillus niger G most effective for producing glucose oxidase (see β- d -glucose:oxygen 1-oxidoreductase, EC 1.1.3.4) was selected out of 110 moulds belonging to 15 different species by the method of test-tube microculture. Conidia of the selected strain were further subjected to mutagenesis with both u.v. and N -methyl- N ′-nitro- N -nitrosoguanidine (NTG) and the products were analysed for glucose oxidase activity with our own diffusion plate method. Among 960 strains isolated after mutagenesis only 12 showed higher activity (from 1.5 to 18%) than the starting strain A. niger G.

Screening and mutagenesis of molds for improvement of the simultaneous production of catalase and glucose oxidase

Abstract A strain of Aspergillus niger (G-IV-10) most effective for simultaneous production of catalase and glucose oxidase (GOD) was selected out of molds belonging to 15 different species by the method of test-tube microculture. Conidia of the selected strain were further subjected to mutagenesis with both UV and n -methyl- n′ -nitro- n -nitrosoguanidine (NTG) and the products were analyzed for catalase activity with our own diffusion plate method. Among 1,055 strains isolated after mutagenesis eight showed higher catalase (from 44.4–102.1%) and GOD (from 8.9 to over 77%) activities than the starting Aspergillus niger G-IV-10.

Optimization of glucose oxidase synthesis in submerged cultures of Aspergillus niger G-13 mutant

Both shaken flask cultures and aerated fermenter cultures of the previously selected Aspergillus niger G-13 mutant were optimized for glucose oxidase production (β-d-glucose: oxygen 1-oxidoreductase, EC 1.1.3.4). The enzyme synthesis was strongly influenced by glucose and calcium carbonate. Optimum results were obtained after about 36 h of fermenter culture when the concentrations of both ingredients were respectively 8 and 3.5%. The crude enzyme preparate obtained by gel filtration Sephadex G-25 column and lyophilization was highly specific for glucose and 2-deoxyglucose, but the latter substrate was oxidized about three times more slowly. The heat stability and pH sensitivity of the enzyme were also studied.

Production of gluconic acid by immobilized in pumice stones mycelium of Aspergillus niger using unconventional oxygenation of culture

Gluconic acid was produced in repeated batch processes with Aspergillus niger AM-11, immobilized in pumice stone particles using an unconventional oxygenation of culture media based on the addition of H2O2, decomposed by catalase to O2 and water. The highest gluconic acid productivity of 8.2 g l−1 h−1 was reached with 30 g immobilized mycelium per 150 ml, 10% (w/v) glucose, at 24 °C and pH 6.5, with O2 at 100% saturation. The immobilized mycelium was successfully reused up to 8 times in 1-h batches with only a slight loss (11%) of gluconic acid productivity.

Selection of biochemical mutants of Aspergillus niger with enhanced catalase production

Abstract The production of extracellular catalase in a submerged culture by a number of biochemical mutants has been evaluated. Eight of these mutants showed increased extracellular catalase, the level of which ranged widely in individual cases from 44% to over 94% in comparison with the parental strain. Studies of the relationship between a criterion of selection and the frequency of mutation showed that the highest frequency of positive mutations (15.8% and 24.2%) was obtained with respect to mutants resistant to ethidium bromide (1 mmol/l) and sodium gluconate (45%) respectively. The time course of growth and enzyme production by the most active mutant, AM-20, showed extra- and intracellular catalase activities increasing about 2- and 2.6-fold respectively, compared with the parental strain.

Penicillium notatum 1 a new source of dextranase

SummaryTwo hundred and fifteen fungal strains were screened for extracellular dextranase production with a diffusion plate method. The best enzymatic activity (12–19 DU ml−1) was achieved byPenicillium notatum 1, a species for which the dextranase productivity has not yet been published. Some of the parameters affecting enzyme production have been standardized. The enzyme in crude state was relatively stable, its maximal activity was at 50°C and at pH 5.0. Conidia of the selected strain were mutagenized, and isolated mutants were tested for production of dextranase in submerged culture. The most active mutant,P. notatum 1-I-77, showed over two-times higher dextranase activity than the parentP. notatum 1

Hydrolysis of dextran by Penicillium notatum dextranase and identification of final digestion products

The basic hydrolysis parameters, i.e. molecular weight of substrate, reaction time, pH, temperature, and enzyme and substrate concentration, were standardized to maximize sugar yield from dextran. Thus, a 74% conversion of 4% dextran to sugar syrup was reached in 12 h using 6 dextranase units g − hydrolysed substrate. The high concentrations of sucrose in the reaction medium did not affect the hydrolysis eaeciency nor the activity of Penicillium notatum dextranase. Action patterns of dextranase from P. notatum on dextran were investigated. Analysis of the dextran hydrolysis end products indicated that P. notatum dextranase was a typical endo-enzyme, and isomaltose and isomaltotriose were identified as the primary final products of dextran hydrolysis.

A novel psychrotrophic fungus, Mortierella minutissima, for D-limonene biotransformation

Of 98 strains of moulds, isolated from arctic soils, Mortierella minutissima 01, grew the best on agar plates with limonene vapor. Perillyl alcohol and perillic acid were the main products of limonene biotransformation. Maximal yield of perillyl alcohol (125 mg l−1) occurred in medium containing 0.8% substrate, at 15 °C, pH 6 and after 4–5 d.