Microbioreactor (micro‐Matrix) potential in aerobic and anaerobic conditions with different industrially relevant microbial strains

Abstract

Microscale fermentation systems are important high throughput tools in clone selection, and bioprocess set up and optimization, since they provide several parallel experiments in controlled conditions of pH, temperature, agitation, and gas flow rate.In this work we evaluated the performance of biotechnologically relevant strains with different respiratory requirements in the micro-Matrix microbioreactor. In particular Escherichia coli K4 requires well aerated fermentation conditions to improve its native production of chondroitin-like capsular polysaccharide, a biomedically attractive polymer. Results from batch and fed-batch experiments demonstrated high reproducibility with those obtained on 2 L reactors, although highlighting a pronounced volume loss for longer-term experiments. Basfia succiniciproducens and Actinobacillus succinogenes need CO 2 addition for the production of succinic acid, a building block with several industrial applications. Different CO 2 supply modes were tested for the two strains in 24 h batch experiments and results well compared with those obtained on lab-scale bioreactors. Overall, it was demonstrated that the micro-Matrix is a useful scale-down tool that is suitable for growing metabolically different strains in simple batch process, however, a series of issues should still be addressed in order to fully exploit its potential.

Optimization of growth of Levilactobacillus brevis SP 48 and in vitro evaluation of the effect of viable cells and high molecular weight potential postbiotics on Helicobacter pylori

“…The broth was centrifuged for 15 min at 10,000 ×g to separate the biomass and recover the supernatant. One ml was then UF/DF on 3 kDa centrifugal filter devices (Centricon, Amicon, and Sigma-Aldrich) at 10,000 ×g and the permeate was analysed for the determination of the concentrations of fructose, glucose, lactic and acetic acids and ethanol by HPLC (UHPLC Dionex Ultimate 3,000; Thermofisher) on a Alltech IOA-2000 column (500 mm × 6.5 mm ID) as previously reported ( D’ambrosio et al, 2021 ).…”

Heterologous production of chondroitin

“…The identification of the enzyme responsible for inserting the fructose residue (KfoE, fructosyltransferase) and its consequent deletion led to the production of unsulfated chondroitin [191] . Genetic engineering has been applied to E. coli K4 to further improve the polysaccharide yields [ 61 , 63 , 187 , 190 , 192 , 193 , 194 , 195 ]. In fact, the highest reported yields so far for biotechnological production of chondroitin have been achieved with genetically engineered E. coli K4 through fed-batch fermentations, reaching 8.43 – 9.2 g/L of fructosylated chondroitin [ 187 , 192 ].…”

Cultivation of microbial cultures at high cell density in microbioreactor fermentations to increase protein yield

“…The micro-Matrix (Applikon) has recently been shown to be a useful scale-down tool for the culturing of several microbial strains. 2 At the present working volumes used in microbioreactors, it is hard to maintain correlations with productionscale vessels. These bioreactors are therefore limited to high-throughput screening: host selection, synthetic biology elements screening, clone selection, and parallel media optimization for batch cultivations.…”

“…In the last 10 years, microbioreactors have become available, for scaled down applications using milliliter volumes. The micro‐Matrix (Applikon) has recently been shown to be a useful scale‐down tool for the culturing of several microbial strains 2 …”