Proizvodnja bioetanola iz kukuruznih oklasaka Ivančić Šantek, Mirela; Zvonar, Ines; Beluhan, Sunčica ...
Kemija u industriji,
7/2018, Letnik:
67, Številka:
7-8
Journal Article, Paper
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Bioetanol je proizveden procesom istodobne saharifikacije i fermentacije (eng. Simultaneous saccharification and fermentation, SSF) s kvascem Saccharomyces cerevisiae na enzimskom hidrolizatu ...predobrađenih kukuruznih oklasaka. Istraživan je učinak trajanja predhidrolize kukuruznih oklasaka na učinkovitost procesa proizvodnje bioetanola te je uspoređen s konvencionalnim procesom SSF. Dvije smjese komercijalno dostupnih enzima rabljene su za hidrolizu sirovine; prva je sadržavala Celluclast 1.5L (Sigma) i β-glukozidazu (Carl Roth), a druga smjesa Celluclast 1.5L (Sigma) i Viscozyme L (Sigma).
Dva dana predhidrolize imala su pozitivan učinak na prinos bioetanola, dok je dulje trajanje predhidrolize smanjilo prinos bioetanola. Najveća koncentracija etanola od 41,24 g dm–3 postignuta je u procesu SSF uz dva dana predhidrolize koja je iznosila 63,15 % teoretskog iskorištenja izračunatog na neobrađeni kukuruzni oklasak. Najveća ukupna produktivnost procesa od 0,36 g dm–3 h–1 postignuta je konvencionalnim SSF-om uz enzimsku smjesu koja je sadržavala Celluclast 1.5L (Sigma) i Viscozyme L (Sigma). Koncentracija etanola iznosila je 36,6 g dm–3, što je 56,02 % teoretskog prinosa etanola na neobrađeni kukuruzni oklasak.
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Surface — culture conditions affecting the biosynthesis of cellulolytic enzymes by Penicillium funiculosum 515 on different agricultural wastes such as wheat bran, wheat straw, corn stems and corn ...cobs were investigated.
P. funiculosum 515 was cultivated on moistened milled substrates. Every day for 7 to 9 days of cultivation the samples were taken, extracted with water and then filtered. Cellulolytic activity of the filtrates obtained was determined on cotton, filter paper (Mandels and Weber 1969) and carboxymethylcellulose (Verhovceva 1965). The sugars produced were measured according to Somogyi (Nelson 1944).
Conditions for preparing inoculum were evaluated: the use of the conidia grown on malt agar or wheat bran, the use of mycelial inoculum and media composition for inocula cultivation. The highest cellulase
yield was achieved when mycelia grown in media containing salts according to Reese et al. (1950), 0.5#/o peptone, 0,l°/o Tween 80 (Mandels et al. 1975) and l°/o cellulosic substrate were used as inocula.
The salts composition used along with water for moistening media were examined and it was found that the composition according to Reese et al. (1950) was the optimal one.
Depending on basic substrate in media the different ratio and degrees of cellulolytic activities of single components were obtained. The maximum time for every single component synthesis of cellulase complex depended on the composition of cultivation media.
P. funiculosum 515 was able to grow on all tested cellulosic wastes and to produce cellulolytic enzymes as well.
Het Praktijkonderzoek Veehouderij is trekker van het EU-project Automatisch Melken, verdeeld in drie onderzoeksvelden en elf onderzoeksaspecten. In de periode 1997-2001 deed PV onderzoek naar de ...melkkwaliteit op melkveebedrijven met een automatisch melksysteem in Nederland, Duitsland en Dememarken. Het verloop van de kwaliteitskenmerken kiemgetal, celgetal, vriespunt en zuurtegraad van het melkvet in de periode na omschakeling op automatisch melken, in vergelijking met bedrijven met een gangbare melkstal. De zuurtegraad van het melkvet is een punt van aandacht
Moderate udder health on high-tech farm Thomassen, I; Poelarends, J; Kamp, A. van der
Praktijkkompas Rundvee (Netherlands),
(2002), Letnik:
16, Številka:
4
Journal Article
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