Lactate and ethanol productions by Rhizopus oryzae ATCC 9363 and activities of related pyruvate branch point enzymes

In Rhizopus oryzae cultivations, lactate production decreased and ethanol and biomass productions increased as inoculated spore concentration increased. Spore concentrations of 1x10(3) and 1x10(4) spores ml(-1) induced tightly packed clumps, whereas 1x10(5) and 1 X 10(6) spores ml(-1) induced filamentous growth

Processing of hazelnut (Corylus avellana L.) shell autohydrolysis liquor for production of low molecular weight xylooligosaccharides by Aureobasidium pullulans NRRL Y-2311-1 xylanase

Buyukkileci, Ali Oguz/0000-0002-0784-0008WOS:000619116700004In this study, a versatile process for the production of xylooligosaccharides (XOS) with a low degree of polymerization (DP 2-6) from hazelnut shells was designed. This process included autohydrolysis integrated with sequential enzymatic hydrolysis by crude xylanase produced with Aureobasidium pullulans NRRL Y-2311-1 from wheat bran. Autohydrolysis of hazelnut shells was carried out at a solid:liquid ratio of 1:6 (w/w) and 190 degrees C nonisothermally. The effects of several parameters on enzymatic hydrolysis of the autohydrolysis liquor were determined. The maximum XOS (DP 2-6) production was 22.5 g/L which was obtained at pH 5.0 and 40 degrees C using enzyme concentration of 240 U/g XOS and substrate concentration of 72 g/L. Under these conditions, 31.29 % of the substrate (total XOS) was converted to low-DP-XOS; xylobiose and xylotriose are being the major oligomers. This is the first study on the application of A. pullulans xylanase in production of xylooligomers from hazelnut shells.Scientific and Technological Research Council of Turkey-TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TOVAG 213O126, TOVAG 112O521]This work was financially supported by The Scientific and Technological Research Council of Turkey-TUBITAK (Project Numbers: TOVAG 213O126 and TOVAG 112O521)

Exploitation of Agricultural Wastes and By-Products for Production of Aureobasidium pullulans Y-2311-1 Xylanase: Screening, Bioprocess Optimization and Scale Up

WOS: 000398594100040The potential of several agricultural wastes and by-products (wheat bran, oat bran, corn cob, brewer's spent grain, malt sprout, artichoke stem, sugar beet pulp, olive seed, cotton stalk and hazelnut skin) was examined as the substrate for xylanase production by Aureobasidium pullulans Y-2311-1. Based on the screening studies, wheat bran was selected as the best substrate for further optimization studies. The effects of initial medium pH, temperature and incubation time on xylanase production in shake flask system were optimized by response surface methodology (RSM). The optimum levels of the process variables defined by the model (initial medium pH, 4.24; temperature, 30.27 degrees C; and incubation time 126.67 h) resulted in production of 85.19 U/ml xylanase. Taking the RSM optimized parameters in shake-flask scale into consideration; xylanase production was scaled up to bioreactor system with a working volume of 1.5 l. The peak of enzyme production was achieved after 126 h incubation that has previously been determined by RSM studies at shake flask level. Furthermore, the optimum levels of agitation and aeration in bioreactor system was found as 200 rpm and 1.5 vvm. Maximum enzyme production was close to 85 kU/l which could be translated into a productivity of 0.68 kU/l/h. No previous work considered the statistical optimization of xylanase production by A. pullulans on wheat bran and scale up of the bioprocess to a bioreactor system.Scientific and Technological Research Council of Turkey-TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TOVAG 112O521]; Ege University Science and Technology Center-EBILTEMEge University [2013/BIL/025]This work was financially supported by The Scientific and Technological Research Council of Turkey-TUBITAK (Project No: TOVAG 112O521) and Ege University Science and Technology Center-EBILTEM (Project No: 2013/BIL/025). S. Yegin is a management committee member in Cost Action TD1203 entitled as Food Waste Valorization for Sustainable Chemicals, Materials and Fuels (EUBis)