Search

Your search keyword '"Steyn, Laurinda"' showing total 12 results
Start Over Author "Steyn, Laurinda" Publication Year Range Last 10 years
12 results on '"Steyn, Laurinda"'

11. Optimization of cultivation conditions for biotechnological production of lipid by Rhodotorula kratochvilovae(syn, Rhodosporidium kratochvilovae) SY89 for biodiesel preparation

Author

Jiru, Tamene, Groenewald, Marizeth, Pohl, Carolina, Steyn, Laurinda, Kiggundu, Nicholas, and Abate, Dawit

Abstract

Rhodotorula kratochvilovae(syn, Rhodosporidium kratochvilovae) SY89, an oleaginous yeast, isolated from Ethiopian soil, was grown under nitrogen-limited media. The capacity this with respect to biomass production, lipid yield and lipid content was evaluated. The influence of inoculum size, carbon sources, variations in glucose concentration, nitrogen sources, C/Nratio, pH, temperature, agitation, and aeration rate and incubation period were investigated. Inoculum size of 10% v/v, glucose as a carbon source at 50 g/L glucose, 0.50 g/L yeast extract and 0.31 g/L (NH4)2SO4, C/Nratio of 120, pH 5.5, incubation temperature of 30 °C, 225 rpm, 0.2 as aeration ratio and 144 h of incubation were found to be optimum conditions for lipid production. Then the yeast was grown in a batch bioreactor by combining the different optimized parameters together. Under the optimized conditions, the yeast gave maximum biomass (15.34 ± 1.47 g/L), lipid yield (8.60 ± 0.81 g/L) and lipid content (56.06 ± 1.70%). The dominant fatty acids exhibited in order of their relative abundance (%w/w), were oleic, palmitic, linoleic, stearic, linolenic and palmitoleic acids. The concentration of saturated and monounsaturated fatty acids adds up 78.63 ± 2.19%. This suggests that this strain could be used as a good feedstock for biodiesel production.

Published
2017
Full Text
View/download PDF

12. Protein enrichment of an Opuntia ficus-indica cladode hydrolysate by cultivation of Candida utilis and Kluyveromyces marxianus.

Author

Akanni, Gabriel B, du Preez, James C, Steyn, Laurinda, and Kilian, Stephanus G

Subjects
PROTEIN analysis, OPUNTIA ficus-indica, CANDIDA utilis, KLUYVEROMYCES marxianus, SINGLE cell proteins, YEAST, BIOMASS energy
Abstract

BACKGROUND The cladodes of Opuntia ficus-indica (prickly pear cactus) have a low protein content; for use as a balanced feed, supplementation with other protein sources is therefore desirable. We investigated protein enrichment by cultivation of the yeasts Candida utilis and Kluyveromyces marxianus in an enzymatic hydrolysate of the cladode biomass. RESULTS Dilute acid pretreatment and enzymatic hydrolysis of sun-dried cladodes resulted in a hydrolysate containing (per litre) 45.5 g glucose, 6.3 g xylose, 9.1 g galactose, 10.8 g arabinose and 9.6 g fructose. Even though K. marxianus had a much higher growth rate and utilized l-arabinose and d-galactose more completely than C. utilis, its biomass yield coefficient was lower due to ethanol and ethyl acetate production despite aerobic cultivation. Yeast cultivation more than doubled the protein content of the hydrolysate, with an essential amino acid profile superior to sorghum and millet grains. CONCLUSIONS This K. marxianus strain was weakly Crabtree positive. Despite its low biomass yield, its performance compared well with C. utilis. This is the first report showing that the protein content and quality of O. ficus-indica cladode biomass could substantially be improved by yeast cultivation, including a comparative evaluation of C. utilis and K. marxianus. © 2014 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results