Oxygen transfer coefficient and the kinetic parameters of exo-polygalacturonase production byAspergillus flavipesFP-500 in shake flasks and bioreactor

Abstract

Aims: To evaluate and compare the sensitivity of Exo-PG production and kinetic parameters of Aspergillus flavipes FP-500 to oxygen transfer condition in shake flasks and bioreactor. Methods and Results: Aspergillus flavipes FP-500 was grown on pectin as carbon source in shake flasks and bioreactor at different oxygen transfer conditions. The volumetric coefficient of oxygen transfer (k L a) was modified by changing both, the flask size/medium volume ratio and the agitation speed. Higher biomass concentration, Exo-PG activity, maximum specific growth rate and yield coefficient were obtained in bioreactor at higher k L a value. A strong correlation was found between biomass, Exo-PG activity and growth-associated product coefficient to k L a in bioreactor but does not in shake flasks. The mathematical model provided a good description of growth, pectin consumption and Exo-PG production in submerged batch cultures carried out in bioreactor. Conclusions: Biomass concentration, Exo-PG activity and their kinetics of Aspergillus flavipes FP-500 were strongly influenced by oxygen transfer condition and cultivation system. Significance and Impact of Study: The production of enzymes by fungal fermentation is strictly aerobic and understanding the influence of oxygen transfer condition on the production kinetic is of vital importance in order to design, optimize and translate bioprocesses to industrial scale.

Sustainable bioproduction of the blue pigment indigoidine: Expanding the range of heterologous products inR. toruloidesto include non-ribosomal peptides

“…The filling volume, and correspondingly the headspace of a culture, is recognized to impact oxygen transfer from the gaseous into the liquid phase. [31][32][33] Thus, to characterize the effect of oxygen transfer and cultivation temperature on the efficiency of indigoidine production, we compared indigoidine production of BlueBelle cultivated in 55 ml culture tubes using three different filling volumes (3 mL, 5 mL and 10 mL corresponding to 5%, 9% and 18% filling volume) and three different temperatures (18°C, 25°C and 30°C) after 3 days in standard synthetic defined media with a starting concentration of 100 g L −1 glucose and 5 g L −1 of ammonium sulfate. Oxygenation is a step required for the formation of indigoidine from glutamine.…”

Insights into the cellular responses to hypoxia in filamentous fungi

“…High oxygen uptake rates of the mycelium exceed the transfer rate into the medium and growth conditions will actually become microaerobic, which means that the low oxygen supply acts as a primary growth limiting factor. The above-described conditions have lately been experimentally verified and constituted a frequent draw back in the fermentation of fungi with biotechnological relevance, like A. flavipes or A. terreus (Gómez Sánchez et al 2012;Fig. 1 Growth of Aspergilli in a normoxic and a hypoxic atmosphere.…”

Extraction and Identification of Anthocyanins in Corn Cob and Corn Husk from Cacahuacintle Maize

“…Since the residual material left after maceration extraction still possessed an intense color, it was decided to carry out an EAE. For that purpose, an enzymatic cocktail obtained from the fermentation of corn cob by Aspergillus flavipes FP‐500 was used and combined with two commercial enzyme cocktails namely Celluclast and Depol 740 L. The enzymatic cocktail from Aspergillus flavipes was used since this strain is known to produce pectinases and xylanases when growing on different agroindustrial residues, including the corn husk and corn cob (Torres‐Barajas & Aguilar‐Osorio, )(Martínez‐Trujillo, Aranda‐Barradas, & Aguilar‐Osorio, )(Gómez‐Sánchez, Martínez‐Trujillo, & Aguilar‐Osorio, )(Wolf‐Márquez et al., ).…”