Kinetics of biomass formation and citric acid production byAspergillus niger on pilot plant scale

1981 ◽  
Vol 23 (11) ◽  
pp. 2433-2445 ◽  
Author(s):  
Max Roehr ◽  
Otto Zehentgruber ◽  
Christian P. Kubicek
Keyword(s):  
Citric Acid ◽  
Pilot Plant ◽  
Acid Production ◽  
Citric Acid Production ◽  
Biomass Formation ◽  
Pilot Plant Scale ◽  
Kinetics Of

scholarly journals A Kinetic model for submerged citric acid production by Aspergillus versicolor using oil palm empty fruit bunch

2021 ◽  
Vol 17 (1) ◽  
pp. 033-040
Author(s):  
Mina Grace Asoka ◽  
Gideon Orkwagh Abu ◽  
Obioma Kenechukwu Agwa
Keyword(s):  
Citric Acid ◽  
Acid Production ◽  
Glucose Consumption ◽  
Logistic Equation ◽  
Citric Acid Production ◽  
Aspergillus Versicolor ◽  
Empty Fruit Bunch ◽  
Batch System ◽  
Reasonable Description ◽  
Kinetics Of

The fermentation kinetics of citric acid by Aspergillus versicolor was studied in a submerged batch system. The logistic equation for growth, the Luedeking–Piret equation for citric acid production and modified Luedeking–Piret-like equation for glucose consumption was proposed for this study. The model appeared to provide a reasonable description for each parameter during the growth phase. The production of citric acid was growth-associated.

scholarly journals Μεταβολισμός της γλυκερόλης στη ζύμη Yarrowia lipolytica και προοπτικές ανάπτυξης νέων βιοδιεργασιών

2011 ◽  
Author(s):  
Άννα Μακρή
Keyword(s):  
Fatty Acid ◽  
Citric Acid ◽  
High Activity ◽  
Yarrowia Lipolytica ◽  
Acid Production ◽  
Dry Weight ◽  
Yeast Cells ◽  
Citric Acid Production ◽  
Biomass Formation ◽  
Formation Phase

In this thesis the metabolism of glycerol in Yarrowia lipolytica ACA–DC 50109, with emphasis on glycerol conversion into value–added biotechnological products, such as single cell oils and citric acid, was studied.The growth of Y. lipolytica was studied in bioreactor batch cultures in multiple limited medium and three distinct phases were identified during growth cycle. In each phase, yeast cells were characterized by specific morphological and biochemical features: biomass formation phase (in which 4–4.5 g/l of biomass were synthesized), lipogenic phase (in which 20–22% lipids wt/wt in dry weight were accumulated in biomass, containing 90% wt/wt neutral lipids) and citric acid production phase (in which 14–30 g/l of citric acid were secreted in the growth environment). Distinct cellular forms of Y. lipolytica were developed during the above phases: in biomass formation phase short true mycelia and pseudo–mycelia were predominant while a few yeast–like cells were observed, in lipogenic phase large obese cells were predominant and in citric acid production phase cells size was diminished.Glycerol passes into the microbial cell by facilitated diffusion. Y. lipolytica successfully converts glycerol via phosphorylation pathway, in which glycerol kinase (GK) and glycerol–3–P–dehydrogenase are implicated. Though high activity of NAD+ dependent isocitric dehydrogenase (NAD+–ICDH) was detected during biomass formation phase, this activity was significantly decreased afterwards inducing lipogenesis. Surprisingly, storage (neutral) lipid turnover and synthesis of glycolipids, sphingolipids and phospholipids – Ρ simultaneously occurred with citric acid production, and happened when GK activity was considerably reduced and NAD+–ICDH activity was minimised. Oleic acid was the major fatty acid in all lipid fractions and phosphatidylcholine – PC was the main Ρ.In continuous culture in nitrogen limited medium Y. lipolytica accumulated low quantities of lipids (~10% w/w, in dry weight), maybe due to the fact that there was not a region of specific dilution rate (D, h–1) in which the key–enzymes that are implicated in lipogenesis (i.e. ΑΣΡ:citrate lyase – ATP:CL and malic enzyme – ME) presented simultaneously high activity while NAD+–ICDH activity was insignificantly decreased in low D. ATP:CL presented high activity (60–300 Units/mg DW) in D 0,033 h–1 while ME presented maximum activity (650 Units/mg DW) inD=0,104 h–1. Lipids were more unsaturated in intermediate D values whilephosphatidylethanolamine – PE, phosphatidylinositol – PI and PC are the main Ρclasses. As far as the morphology is concerned, in D<0,055 h–1 short true mycelia andpseudo–mycelia were predominant in culture medium while in D 0,055 h–1 onlyyeast cells were observed.In experiments performed in nitrogen limited medium in D=0,026 h–1 indifferent dissolved oxygen – DO concentrations, it was found that in extreme DOvalues ( 70% and 7%) the percentage of P was increased. Independently the DOconcentration PC was the main class followed by PI and PE. The morphology of Y.lipolytica was influenced by the different concentration of DO and it was observedthat in DΟ 50% short true mycelia and pseudo–mycelia were predominant in culturemedium while in DΟ 50% more yeast cells were appeared.In experiments performed in D=0,026 h–1, it was found that the absence ofmicronutrients from the growth medium, i.e. magnesium and calcium that areimplicated in multiple cellular functions, had severe effects in yeast physiology, whilethe fatty acid composition of cellular lipids was not affected by the nature of thegrowth limiting factor.The present thesis aspires to contribute in the study of oleaginousmicroorganisms’ physiology and in use of glycerol as substrate in futurebiotechnological applications.

Effect of Various Parameters on Citric Acid Production using Different Substrates

2012 ◽  
Vol 3 (7) ◽  
pp. 1-3
Author(s):  
Pawar V.A Pawar V.A ◽  
◽  
Pawar P.R Pawar P.R
Keyword(s):  
Citric Acid ◽  
Acid Production ◽  
Citric Acid Production

scholarly journals The Effect of Lipids on Citric Acid Production by an Aspergillus niger Mutant

1963 ◽  
Vol 30 (3) ◽  
pp. 365-379 ◽  
Author(s):  
N. F. MILLIS ◽  
B. H. TRUMPY ◽  
B. M. PALMER
Keyword(s):  
Citric Acid ◽  
Aspergillus Niger ◽  
Acid Production ◽  
Citric Acid Production

Optimization of Trace Metals Concentration on Citric Acid Production by Aspergillus niger NRRL 2001

2007 ◽  
Vol 1 (3) ◽  
pp. 246-253 ◽  
Author(s):  
A. A. Guilherme ◽  
G. A. S. Pinto ◽  
S. Rodrigues
Keyword(s):  
Citric Acid ◽  
Trace Metals ◽  
Aspergillus Niger ◽  
Acid Production ◽  
Citric Acid Production
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