Search

Uporaba fosilnih goriv je zaradi sproščanja toplogrednih plinov vse večji okoljevarstveni problem, zato je pomembno iskanje novih, trajnostnih in okolju prijaznejših virov energije. Biogoriva druge generacije imajo velik potencial za razvoj trajnostne ekonomije. Pridobivajo jih z razgradnjo in fermentacijo lignocelulozne biomase, ki je najbolj razširjen in cenovno ugoden obnovljiv substrat. Za razvoj proizvodnje biogoriv je ključno iskanje novih encimov za razgradnjo biomase, saj ti zaenkrat zaradi visoke cene, premajhne učinkovitosti in slabe stabilnosti v procesnih razmerah še ne dosegajo povpraševanja. V magistrski nalogi smo v metagenomski DNA komposta identificirali ksilanazo iz družine GH10 z dvema vezavnima domenama za ogljikove hidrate (CBM). Tarčni gen (xylM_3) smo prenesli v ekspresijski sev in analizirali izražanje produkta pri različnih pogojih. Ugotovili smo, da se produkt tarčnega gena optimalno izraža ob dodatku 0,75 mM IPTG, največ aktivnega encima pa dobimo po 20-urni inkubaciji pri 18 °C. Tarčni encim smo poskušali očistiti z afinitetno kromatografijo (Ni-NTA) v nativnih in denaturirajočih pogojih, vendar izoliranega nismo uspeli pridobiti v aktivni obliki. Kljub vsemu smo z analizo encimskih frakcij ugotovili, da je encimski ekstrakt aktiven v temperaturnem območju med 20 in 60 °C in pri pH 5-8, najvišjo aktivnost pa dosega pri temperaturi 50 °C in pH = 6. Pokazali smo tudi, da encimski ekstrakt lahko razgrajuje bukov ksilan in arabinoksilan. Aktivnost encimskega ekstrakta na ksilanu se je povečala ob dodatku 1, 5 in 10 mM K+ in 1 mM Co2+ ter 0,2 mM detergenta Triton-X 100. Ob dodatku ostalih testiranih ionov in kemikalij nismo ugotovili sprememb v encimski aktivnosti ali pa se je ta znižala. The use of fossil fuels is an increasing environmental problem due to the release of greenhouse gases. It has therefore become increasingly important to find new sustainable and more environmentaly friendly energy resources. Second-generation biofuels have great potential for development of bioeconomy as they are obtained by decomposition and fermentation of lignocellulosic biomass, the most widespread and affordable renewable substrate. In recent years a lot of effort has been put into finding novel enzymes, which are the key for the development of cost-effective biofuels production. In the following work, the product of a gene encoding putative xylanase (xylM_3), obtained from metagenomic library of compost microbial community was heterologically expressed and biochemicaly characterized. Bioinformatic analysis of the target gene revealed an enzyme with a single catalytic site belonging to glycoside hydrolase family 10 (GH10) and two carbohydrate-binding modules (CBM 2 and CBM 60). Enzyme was heterologically expressed in E. coli BL21 (DE3). The optimum conditions for the enzyme production were determined. Largest amounts of active enzyme were produced at 0.75 mM IPTG, after 20 hours incubation at 18 °C. The enzyme extract was active in the temperature range between 20 and 60 °C and pH 5-8, with the highest activity measured at 50 °C and pH = 6. The activity of the enzyme extract on beechwood xylan and arabinoxylan was confirmed. The addition of 1, 5 and 10 mM K+, 1 mM Co2+ and 0.2 mM Triton-X 100 increased the xylanolytic activity of the enzyme extract. On the other hand, the enzyme extract retaind the original activity in the presence of of 20 % formic acid, while the addition of other tested organic solvents (methanol, ethanol and acetone) reduced its activity.

Poznamo različne koncepte vzgoje in izobraževanja in vsak od njih se trudi ravnati v dobrobit celostnega razvoja posameznika. V svetu je dobro poznana pedagogika, ki jo je razvijal pedagog nemških korenin, Kurt Hahn. Oblikoval jo je na podlagi osebnih izkušenj in odzivov na družbeno dogajanje v prvi polovici dvajsetega stoletja. Njen glavni namen je oblikovati samostojno, odgovorno, strpno in sočutno osebo, ki bi na podlagi individualno zastavljenih ciljev izluščila iz sebe le najboljše. Na podlagi Hahnove filozofije se je razvil program MEPI ali Mednarodno priznanje za mlade, v katerega je v Sloveniji vključenih več kot 70 osnovnih in srednjih šol in se izvaja pod okriljem Društva MEPI. Na šolah ga izvajajo učitelji, ki so usposobljeni za mentorje in inštruktorje. Vanj se lahko vključijo mladi od štirinajstega do petindvajsetega leta starosti. Ker smo opazili pozitivne učinke pri mladih, ki so program opravljali, in ker menimo, da je lahko odlično dopolnilo k pouku družbe, smo se odločili, da po konceptu MEPI-ja oblikujemo enoletni program za peti razred osnovne šole. Program vključuje načrt dejavnosti po mesecih za eno šolsko leto ter priročnik z učnimi pripravami za izvedbo tridesetih kontaktnih ur mentorja z udeleženci. Pri pripravi dejavnosti smo sledili večinoma učnemu načrtu za družbo v petem razredu ter konceptu programa MEPI. Tako smo vključili najprej dejavnosti za razvoj individualnih sposobnosti, v drugem delu pa dejavnosti za razvoj veščin timskega dela. Ta del je posvečen pripravam na odpravo, v sklopu katerih pridobivajo učenci znanja s področja prostorske orientacije in kartografije ter preko različnih izzivov socialne veščine. Trudili smo se, da oblikujemo program, ki bi bil zanimiv in poučen za učence, izvajalcem programa pa predstavljal možnost, kako vzpostaviti kontakt z mladimi na malo manj formalen način. Upamo in želimo, da bi ga v praksi preizkusilo čim več izvajalcev, v ta namen bomo delili napisan priročnik z vsemi interesenti. There are different concepts of education and each of them is trying to act for the benefit of the integral development of the individual. There is a well known pedagogy, which has been developed by pedagogue of German roots, Kurt Hahn. It was designed based on personal experiences and responses to social developments in the first half of the twentieth century. Its main purpose is to create an independent, responsible, tolerant and compassionate person who would bring out the best out of them based on their personal goals. Based on the Hahn’s philosophy MEPI program (Duke of Edinburgh’s International Award) was developed, which is included in more than 70 primary and secondary schools in Slovenia and it is carried out under the auspices of Društvo MEPI. In schools it is carried out by teachers who are trained as mentors and instructors. Young people from the fourteenth to twenty-five years of age can join this program. As we have observed positive effects on young people, who were engaged in the program, and because we believe it can be an excellent complement to course of social studies, we decided to design a one-year program for fifth grade of primary school based on MEPI. The program includes action plan by months for one school year and a manual with preparations for the execution of thirty contact hours between mentor and participants. In preparation of activities, we followed mainly curriculum for fifth grade course of social studies, and the concept of the MEPI program. In the first part we included activities for the development of individual skills and in the second part activities to develop teamwork skills. This section is devoted to the preparations for the expedition, under which students acquire knowledge in the field of spatial orientation and mapping as well as through various challenges of social skills. We tried to design a program that would be interesting and instructive for students and for mentors the program represented a possibility, how to establish contact with young people at a little less formal way. We hope and we wish that this program is tested in practice by as many mentors as possible, for this purpose we will share written guide with all interested parties.