title: Effect of multiple short highly energetic X-ray pulses on the synthesis of endoglucanase by a mutant strain ofTrichoderma reesei-M7.
abstract: Bioconversion of cellulose-containing substrate to glucose represents an important area of modern biotechnology. Enzymes for the degradation of the polysaccharide part of biomass have been produced, mostly by fungi belonging to genusTrichoderma. Studies were carried out with the mutant strainTrichoderma reesei-M7, a cellulase producer. Spores of the enzyme producer were irradiated with different doses of characteristic X-ray radiation from metallic tungsten (mainly the W Kα1 and Kα2 lines) with a high dose rate. The latter is a specific property of the dense plasma focus (DPF) device, which has pulsed operation and thus gives short and highly energetic pulses of multiple types of rays and particles. In this case, we focused our study on the influence of hard X-rays. The doses of X-rays absorbed by the spores varied in the range of approximately 5-11,000 mSv measured with thermoluminescent dosimeters (TLD). The influence of the applied doses in combination with exceptionally high dose rates (in the order of tens of millisieverts per microsecond) on the activity of the produced endoglucanase, amount of biomass and extra-cellular protein, was studied in batch cultivation conditions. In the dose range of 200-1200 mSv, some enhancement of endoglucanase activity was obtained: around 18%-32%, despite the drop of the biomass amount, compared with the untreated material.
authors.affiliation: Department of Biotechnology, Faculty of Biology, Sofia University 'St. Kliment Ohridski' , Sofia , Bulgaria.
authors.forename: Orlin
authors.initials: O
authors.lastname: Gemishev
authors.affiliation: Department of Optics and Spectroscopy, Faculty of Physics, Sofia University 'St. Kliment Ohridski' , Sofia , Bulgaria.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Zapryanov
authors.affiliation: Department of Optics and Spectroscopy, Faculty of Physics, Sofia University 'St. Kliment Ohridski' , Sofia , Bulgaria.
authors.forename: Alexander
authors.initials: A
authors.lastname: Blagoev
authors.affiliation: Department of Biotechnology, Faculty of Biology, Sofia University 'St. Kliment Ohridski' , Sofia , Bulgaria.
authors.forename: Maya
authors.initials: M
authors.lastname: Markova
authors.affiliation: Department of Biotechnology, Faculty of Biology, Sofia University 'St. Kliment Ohridski' , Sofia , Bulgaria.
authors.forename: Valentin
authors.initials: V
authors.lastname: Savov
keywords: Trichoderma reesei; X-ray pulses; dense plasma focus (DPF); endoglucanase; thermoluminescent dosimeters (TLD)