Evaluating aeration and stirring effects to improve itaconic acid production from glucose using Aspergillus terreus

Abstract

The effects of the bioreactor conditions, in particular the mode and intensity of aeration and mixing were studied on itaconic acid (IA) fermentation efficiency by Aspergillus terreus strain from glucose substrate. IA was produced in batch system by systematically varying the oxygen content of the aeration gas (from 21 to 31.5 vol% O2) and the stirring rate (from 150 to 600 rpm). The data were analyzed kinetically to characterize the behavior of the process, and besides, the performances were evaluated comparatively with the literature. It turned out that the operation of the bioreactor with either the higher inlet O2 concentration (31.5 vol% O2) or faster stirring (600 rpm) could enhance biological IA generation the most, resulting in yield and volumetric productivity of 0.31 g IA/g glucose and 0.32 g IA/g glucose and 3.15 g IA/L day and 4.26 g IA/L day, respectively. Overall, the significance of fermentation settings was shown in this work regarding IA production catalyzed by A. terreus and notable advances could be realized by adjusting the aeration and stirring towards an optimal combination.Graphic abstract

Optimized Bioproduction of Itaconic and Fumaric Acids Based on Solid-State Fermentation of Lignocellulosic Biomass

“…Regarding the larger scale fermentation in the plastic bag prototype reactor, the improvement in acid production could be explained by the better supply of oxygen and moisture in the fermenter. Indeed, IA fermentation is strictly aerobic, and previous studies showed that a gain in dissolved oxygen and agitation induced higher yields [42,43]. The moisture level could affect the IA production.…”

Investigation of Itaconic Acid Separation by Operating a Commercialized Electrodialysis Unit with Bipolar Membranes

“…The following flow (recirculation) rates were maintained during operation: C base : 50 L/h; D: 50 L/h; C acid : 50 L/h; E: 60 L/h. The feed solutions were formulated as stated in Table 3, based on our previous experiences with IA production and separation [21,22]. The conductance of the solutions (in tanks D, C base , C acid ) over time was measured by a Radelkis OK-102/1 conductivity meter connected to a Radelkis OK-9023 bell electrode using a cell constant of 0.7 cm −1 .…”

“…Compared to the previous experiments (A and B) it seemed that under lower applied potential 20V with higher initial pH 5 and higher IA concentration (around 33g/ L) could result in more efficient columbic efficiency (CE) from the viewpoint of IA separation. In the following tests, low potential (10 V) was set and the initial pH was adjusted to 3, which is an ordinary value in IA fermentation [22]. Table 3 presents the composition of the model solutions (Experiments C., D., E.) which contains: itaconic acid, glucose and malic acid.…”

Recent advances in itaconic acid production from microbial cell factories

“…Krull et al (2017) developed a process based on well-timed and fine-tuned pH control that could generate the highest itaconic acid titer 160 g/L using A. terreus DSM 23081 strain. Other investigations related to the influence of media composition, nitrogen sources, oxygen supply, fermentation techniques, and recovery process on itaconic acid yield by A. terreus have also been conducted (Boruta and Bizukojc, 2017;Karaffa et al, 2015;Kuenz et al, 2012;Kuenz and Krull, 2018;Magalhães et al, 2017;Nemestóthy et al, 2019;Saha et al, 2019).…”