Effect of Nitrogen Concentration on the Biosynthesis of Citric Acid, Protein, and Lipids in the Yeast Yarrowia lipolytica

Abstract

Yarrowia lipolytica yeast is well known to be able to synthesize citric acid (CA) in large amounts. This study deals with CA biosynthesis, the production of biomass, as well as the accumulation and composition of proteins and lipids in Y. lipolytica VKM Y-2373 grown in media with glucose at different concentrations of ammonium sulfate (from 2 to 10 g/L). It was found that these concentrations of nitrogen source are limiting for the growth of Y. lipolytica and that nitrogen deficiency is the main cause of CA excretion. At the high concentration of (NH4)2SO4 (10 g/L), the accumulation of cell biomass, biomass yield (YX/S), and protein concentration was higher than in the medium with 2 g/L ammonium sulfate by 4.3 times, 143%, and 5.1 times, respectively. CA was accumulated in meaningful quantities only in media containing 3–10 g/L (NH4)2SO4 with the maximum concentration of CA (99.9 g/L) at 4 g/L ammonium sulfate. Also of interest is the technological mode with 6 g/L (NH4)2SO4, which is characterized by high productivity (1.11 g/L×h). It should be noted that biomass contains large amounts of essential amino acids and unsaturated fatty acids and can be used in food biotechnologies and agriculture.

Butyric Acid and Caproic Acid Production Using Single and Mixed Bacterial Cultures

“…However, in this study, all experiments were performed with the same C/N ratio, even though the dilution ratio of CW was different. Nitrogen concentration also affects VFA production [24]. In this study, nitrogen concentration as total nitrogen at each dilution was 1.4 g/L (raw CW), 0.7 g/L (two-times-diluted CW), 0.28 g/L (five-times-diluted CW), 0.14 g/L (ten-timesdiluted CW).…”

“…The highest C6 production was observed at 0.7 g/L (Figure 4). Kamzolova et al [24] reported that nitrogen source concentrations limit the growth of Y. lipolytica, and nitrogen deficiency is the main cause of citric acid excretion. Citric acid was accumulated in meaningful quantities only in media containing 3-10 g/L (NH 4 ) 2 SO 4 , with the maximum concentration of citric acid at 4 g/L ammonium sulfate.…”

A Review on Citric Acid Production by Yarrowia lipolytica Yeast: Past and Present Challenges and Developments

“…In general, Y. lipolytica yeast grown on pure substrates such as glucose and glycerol requires between 630 and 1200 mg/L of nitrogen [73]. Kamzolova et al [74] found that the volumetric productivity (Q CA ) was very high (1.11 g/L•h) at a nitrogen concentration of 1200 mg/L. However, waste with a high nitrogen content can be utilized without adding nitrogen to the medium.…”

“…lipolytica yeast uses KH 2 PO 4 , K 2 HPO 4 , and Na 2 HPO 4 as sources of potassium and phosphorus. The concentrations vary from 100 to 2400 mg/L [33,48,74,75].…”

“…This strain was originally obtained in 1963 from activated sludge from the Angarsk oil refinery effluent treatment plant in the USSR. It can produce significant amounts of CA from crude glycerol [44] and glucose [74]. The biomass, a by-product of CA production, possesses a significant quantity of essential amino acids and unsaturated fatty acids, making it suitable for application in the areas of food biotechnology and agriculture [74].…”