Apparent effects of operational variables on the continuous culture of Corynebacterium lactofermentum

Investigation on the Cultivation Conditions of a Newly Isolated Fusarium Fungal Strain for Enhanced Lipid Production

Fusarium equiseti UMN-1 fungal strain isolated from soybean is selected as a potential oleaginous fungal strain for biodiesel generation. It possesses desirable features, such as high lipid content (up to 56%) and high fatty acid methyl ester (FAME) content (more than 98%) in total lipids, and also has the capability to produce cellulase. This research focused on the investigation of the characteristics of this strain and optimization of culture conditions to enhance lipid production. Impact of temperature, agitation, C/N ratio, medium composition, and carbon and nitrogen sources has been observed, and central composite design (CCD) has been applied to improve the lipid accumulation. The optimum range for temperature, agitation, C/N ratio, and carbon and nitrogen concentrations was discovered, and the CCD model with the optimized growth medium and growth conditions achieved a maximum lipid production of 3.89 g/L. This research on F. equiseti UMN-1 fungal strain is expected to improve the feasibility of using microbial lipids of F. equiseti UMN-1 strains as the source of biofuels.

Online medium-throughput respirometry-based OTR measurements in magnetically stirred cultures

Intensified bioprocess development requires parallelized medium- to high-throughput experimentation with high on- and offline data density across all early scales of the development trajectory from microtiter plate via shake flask to lab-scale reactor. We developed a widespread measurement principle for intermediate scales, respirometry, into a parallelized oxygen transfer rate measurement device that could accurately record common process development-relevant effects such as acetate formation, diauxic growth, and nutrient limitations. The device was further equipped with dissolved oxygen measurement capability and sampling ports that allowed repetitive monoseptic sample withdrawal without disturbing the cultivation. Optimization of the operating parameters lead to k(L) a values of up to 160 h(-1) and corresponding oxygen transfer rates of 1 g L(-1) h(-1) for cultivation volumes of 50 mL.