An efficient multi-stage fermentation strategy for the production of microbial oil rich in arachidonic acid in Mortierella alpina

Abstract

BackgroundFungal morphology and aeration play a significant role in the growth process of Mortierella alpina. The production of microbial oil rich in arachidonic acid (ARA) in M. alpina was enhanced by using a multi-stage fermentation strategy which combined fed-batch culture with precise control of aeration and agitation rates at proper times.ResultsThe fermentation period was divided into four stages according to the cultivation characteristics of M. alpina. The dissolved oxygen concentration was well suited for ARA biosynthesis. Moreover, the ultimate dry cell weight (DCW), lipid, and ARA yields obtained using this strategy reached 41.4, 22.2, 13.5 g/L, respectively. The respective values represent 14.8, 25.8, and 7.8% improvements over traditional fed-batch fermentation processes.ConclusionsThis strategy provides promising control insights for the mass production of ARA-rich oil on an industrial scale. Pellet-like fungal morphology was transformed into rice-shaped particles which were beneficial for oxygen transfer and thus highly suitable for biomass accumulation.

An Online Respiratory Quotient-Feedback Strategy of Feeding Yeast Extract for Efficient Arachidonic Acid Production by Mortierella alpina

“…The lipid synthesis was rapidly increased in parallel with the cell growth to achieve 14.8 g/L for the first 65 h, after that it was increased much more slowly from 14.8 to 17.89 g/L and then stopped. Growth-coupled lipid production had been observed in the previous studies for M. alpina (Hwang et al, 2005 ; Wu et al, 2017 ). The ARA titer was increased during the whole cultivation with a final concentration of 8.4 g/L, showing productivity of 1.2 g/L per day.…”

“…The ARA titer was increased during the whole cultivation with a final concentration of 8.4 g/L, showing productivity of 1.2 g/L per day. In the fed-batch fermentation, lipid/dry cell weight (DCW) reached 59.2%, which was much higher than most of the oleaginous fungus (Ling et al, 2016 ; Wu et al, 2017 ). Obviously, low concentration of biomass was a limitation for lipid synthesis because lipid was stored within the existing mycelium, which could no longer divide or elongate.…”

Enhanced Production of Carboxymethylcellulase by Recombinant Escherichia coli Strain from Rice Bran with Shifts in Optimal Conditions of Aeration Rate and Agitation Speed on a Pilot-Scale

“…During fermentation with the multistage bioreactors, the first bioreactor containing microorganisms in the growth phase was for the cell growth and the second bioreactor containing non-proliferating cells was for the production of metabolites [28]. The production of the arachidonic acid by M. alpina was increased by using continuous multistage fermentation with precise control of the agitation speed and aeration rate at proper times [29]. The multistage chemostat system may be beneficial for improving the genetic stability and production of metabolites [20,30].…”

Application of high EPA-producingMortierella alpinain laying hen feed for egg DHA accumulation

“…However, among these additives, M. alpina has many advantages, such as higher conversion of EPA to DHA, an advanced fermentation process, and lower cost (Table 6). 25,31,32…”