Extracellular catalase production by Aspergillus phoenicis.

Poster (2004, May)

Overproduction of lipase by Yarrowia lipolytica mutants

in Applied Microbiology & Biotechnology (2003), 63(2), 136-142

Non-genetically modified mutants with increased capacities of extracellular lipase production were obtained from Yarrowia lipolytica strain CBS6303 by chemical mutagenesis. Of the 400 mutants isolated ... [more ▼]

Non-genetically modified mutants with increased capacities of extracellular lipase production were obtained from Yarrowia lipolytica strain CBS6303 by chemical mutagenesis. Of the 400 mutants isolated, LgX64.81 had the highest potential for the development of an industrial lipase production process. This mutant exhibits lipase production uncoupled from catabolite repression by glucose, and a 10-fold increased productivity upon addition of oleic acid. Using a LIP2-LacZ reporter gene, we demonstrate that the mutant phenotype originates from a trans-acting mutation. The glucose uptake capacity of LgX64.81 is reduced 2.5-fold compared to the wild-type-strain, and it exhibits high lipase production on glucose medium. A trans-acting mutation in a gene involved in glucose transport could thus explain this mutant phenotype. [less ▲]

"Gas-liquid hydrodynamic in stirred vessel : modelling and application to a Penicillium fermentation "

Conference (2003, August 24)

Bacteriocin production and inhibition of Listeria monocytogènes by Lactobacillus curvatus CWBI-B28 in cold smoked salmon

Poster (2003, June)

Monitoring of the de-esterification and depolymerisation of pectins by nirs.

Poster (2003, May 09)

Cellulose enzymatic availability in Municipal solid waste

in Christensen; Cossu; Stegmann (Eds.) Proceedings Sardinia 03, Ninth International Waste Management and Landfill Symposium (2003)

We recently developed a new and rapid method to evaluate the biological reactivity of cellulose in Municipal Solid Waste (MSW). This test is based on the enzymatic hydrolysis of cellulose in MSW and can ... [more ▼]

We recently developed a new and rapid method to evaluate the biological reactivity of cellulose in Municipal Solid Waste (MSW). This test is based on the enzymatic hydrolysis of cellulose in MSW and can be related to the digestibility of this polymer in MSW. In this work, we showed that the enzymatic cellulose degradation test (ECD) correlated well with a Biochemical Methane Potential (BMP) assay so that the ECD test can be reliably applied to estimate cellulose bioavailability in various waste samples. These tests have also been used to evaluate the influence of some important parameters that could affect the extent and the rate of cellulose degradation in waste. It appeared that cellulose enzymatic hydrolysis is related to the moisture content but no clear relationship could be established with the cellulose content. Moreover, it is shown that acetic acid produced by the anaerobic degradation of organic matter, and responsible for high COD in young leachates, may slow down or inhibit the enzymatic hydrolysis step and the methanogenesis. [less ▲]

Cellulose bioavailability in waste

Poster (2002, October)

Lipase production in Yarrowia lipolytica overproducing mutants.

Poster (2002, July)

Screening of pectolytic microorganisms by near infrared reflectance spectroscopy.

Poster (2001, June)

A pluridisciplinary model to predict municipal landfill life

Conference (2001)

Most degradation processes that occur within municipal wastes landfills result from different microbial activities interacting all along the landfill lifetime and that are influenced by several non ... [more ▼]

Most degradation processes that occur within municipal wastes landfills result from different microbial activities interacting all along the landfill lifetime and that are influenced by several non-biological factors. These complex biological and chemical processes require a multidisciplinary pattern in order to assess and control their environmental impact. Thanks to Walloon Region support, we have developed a pattern or model combining the evolution of different key parameters. Such parameters qualify biogas (composition, production rate), leachate (pH, BOD5, COD, volatile fatty acids, redox potential, nitrogen balance, humic acids...), or solid waste (moisture, settlement, cellulose content...). This paper presents relationships, including our model, between these parameters. Variations of pH, BOD5/COD ratio, sulfate concentration in leachates, gas composition analysis and settlement measures allow to predict landfill age, on a standard scale, since completion. Evaluation of cellulose and water content in refuse as well as settlement degree are useful to estimate the time required for complete biological degradation. [less ▲]