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Lecanicillium muscarium CCFEE 5003, isolated in Continental Antarctica, is a powerful producer of extracellular cold-tolerant enzymes. Chitin-hydrolyzing enzymes seems to be the principal extracellular catalytic activities of this psychrotolerant fungus. The production of chitinolytic activities is induced by chitin and other polysaccharides and is submitted to catabolite repression. The chitinolytic system of L. muscarium consists of a number of different proteins having various molecular weights and diverse biochemical characteristics, but their most significant trait is the marked cold-tolerance. L. muscarium and selected strains of the biocontrol agent of pathogenic fungi Trichoderma harzianum, have been compared for their ability to produce chitinolytic enzymes at different temperatures. At low temperatures the Antarctic strain was definitely much more efficient. Moreover, the fungus was able to exert a strong mycoparasitic action against various other fungi and oomycetes at low temperatures. The parasitic role of this organism appeared related to the production of cell wall degrading enzymes being the release of extracellular chitinolytic enzymes a key event in the mycoparasitic process. Due to the mentioned characteristics, L. muscarium could have an important role for potential applications such as the degradation of chitin-rich materials at low temperature and the biocontrol of pathogenic organisms in cold environments. For these reasons and in view of future industrial application, the production of chitinolytic enzymes by the Antarctic fungus has been up-scaled and optimised in bench-top bioreactor.

The Antarctic fungus Lecanicillium muscarium CCFEE-5003 was preliminary cultivated in shaken flasks to check its chitinase production on rough shrimp and crab wastes. Production on shrimp shells was much higher than that on crab shells (104.6±9.3 and 48.6±3.1U/L, respectively). For possible industrial applications, bioprocess optimization was studied on shrimp shells in bioreactor using RSM to state best conditions of pH and substrate concentration. Optimization improved the production by 137% (243.6±17.3). Two chitinolytic enzymes (CHI1 and CHI2) were purified and characterized. CHI1 (MW ca. 61kDa) showed optima at pH 5.5 and 45°C while CHI2 (MW ca. 25kDa) optima were at pH 4.5 and 40°C. Both enzymes maintained high activity levels at 5°C and were inhibited by Fe(++), Hg(++) and Cu(++). CHI2 was strongly allosamidin-sensitive. Both proteins were N-acetyl-hexosaminidases (E.C. 3.2.1.52) but showed different roles in chitin hydrolysis: CHI1 could be defined as "chitobiase" while CHI2 revealed a main "eso-chitinase" activity., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: The Antarctic fungus Lecanicillium muscarium CCFEE 5003 is one of the most powerful chitinolytic organisms. It can produce high level of chitinolytic enzymes in a wide range of temperatures (5-30°C). Chitinolytic enzymes have lot of applications but their industrial production is still rather limited and no cold-active enzymes are produced. In view of massive production of L. muscarium chitinolytic enzymes, its cultivation in bioreactors is mandatory. Microbial cultivation and/or their metabolite production in bioreactors are sometime not possible and must be verified and optimized for possible exploitation. Agitation and aeration are the most important parameters in order to allow process up-scaling to the industrial level., Results: In this study, submerged cultures of L. muscarium CCFEE 5003 were carried out in a 2-L bench-top CSTR bioreactor in order to optimise the production of chitinolytic enzymes. The effect of stirrer speed (range 200-500 rpm) and aeration rate (range 0.5-1.5 vvm) combination was studied, by Response Surface Methodology (RSM), in a medium containing 1.0% yeast nitrogen base and 1% colloidal chitin. Optimization was carried out, within a "quadratic D-optimal" model, using quantitative and quantitative-multilevel factors for aeration and agitation, respectively. The model showed very good correlation parameters (R2, 0.931; Q2, 0.869) and the maximum of activity (373.0 U/L) was predicted at ca. 327 rpm and 1.1 vvm. However, the experimental data showed that highest activity (383.7 ± 7.8 U/L) was recorded at 1 vvm and 300 rpm. Evident shear effect caused by stirrer speed and, partially, by high aeration rates were observed. Under optimized conditions in bioreactor the fungus was able to produce a higher number of chitinolytic enzymes than those released in shaken flasks. In addition, production was 23% higher., Conclusions: This work demonstrated the attitude of L. muscarium CCFEE 5003 to grow in bench-top bioreactor; outlined the strong influence of aeration and agitation on its growth and enzyme production and identified the optimal conditions for possible production at the industrial level.

The possible use of olive-mill wastewater (OMW) as a growth medium for the production of extracellular laccase and manganese peroxidase (MnP) from the white-rot fungus Panus tigrinus (P. tigrinus) CBS 577.79 was studied using a properly formulated OMW-based medium (2-fold diluted OMW supplemented with 0.5% sucrose and 0.1% yeast extract) either in a stirred-tank or an air-lift reactor. Solid-state fermentation (SSF) was also performed in a rotary drum reactor using maize stalks moistened with the OMW-based medium. Highest levels of laccase and manganese peroxidase activity were obtained in the stirred-tank reactor (4600+/-98 U l(-1) on day 13) and in the air-lift reactor (410+/-22 on day 7), respectively. Based on total enzyme activities, SSF appears to be more suitable than LSF but the latter exhibits better volumetric productivities.

Polyphenols and their intermediate metabolites are natural compounds that are spread worldwide. Polyphenols are antioxidant agents beneficial for human health, but exposure to some of these compounds can be harmful to humans and the environment. A number of industries produce and discharge polyphenols in water effluents. These emissions pose serious environmental issues, causing the pollution of surface or groundwater (which are used to provide drinking water) or harming wildlife in the receiving ecosystems. The treatment of high-polyphenol-content waters is mandatory for many industries. Nowadays, biotechnological approaches are gaining relevance for their low footprint, high efficiency, low cost, and versatility in pollutant removal. Biotreatments exploit the diversity of microbial metabolisms in relation to the different characteristics of the polluted water, modifying the design and the operational conditions of the technologies. Microbial metabolic features have been used for full or partial polyphenol degradation since several decades ago. Nowadays, the comprehensive use of biotreatments combined with physical-chemical treatments has enhanced the removal rates to provide safe and high-quality effluents. In this review, the evolution of the biotechnological processes for treating high-polyphenol-content water is described. A particular emphasis is given to providing a general concept, indicating which bioprocess might be adopted considering the water composition and the economic/environmental requirements. The use of effective technologies for environmental phenol removal could help in reducing/avoiding the detrimental effects of these chemicals. In addition, some of them could be employed for the recovery of beneficial ones. [ABSTRACT FROM AUTHOR]

Abstract: The white-rot fungus Panus tigrinus CBS 577.79 was cultivated both in mechanical (stirred tank, STR) and pneumatically (bubble column, BCB) agitated bioreactors and investigated for its ability to reduce the polluting load of olive-mill wastewater (OMW). Both aeration and agitation strongly influenced treatment efficiency. Best pollutants biodegradation performances were achieved in the bubble column bioreactor. Using this bioreactor, COD reduction, dephenolization and decoloration were 60.9, 97.2 and 75%, respectively. In contrast, lower depollution efficiency was generally observed in STR due to the possible occurrence of shear stress. [Copyright &y& Elsevier]