Lignocellulose is an abundant raw material and renewable carbon source for the production of single cell oils which can replace plant-derived oils in food, feed, fuels, and oleochemicals. Mucor circinelloides produces both fatty acids and amino polysaccharides, such as chitin and chitosan. This study evaluates hydrolysates of Norway spruce (Picea abies) as a carbon source for their simultaneous production. Cultivation in spruce hydrolysate media yielded 15.8 g/L of biomass, with fatty acids comprising ~ 50% of the cell dry weight and amino polysaccharides up to 8.5%. The fatty acid methyl ester (FAME) content and fatty acid profile were comparable to glucose fermentation. Optimal harvesting times ranged from 72 to 120 h, depending on desired yields. These findings demonstrate that Norway spruce hydrolysates are a viable and sustainable substrate for microbial lipid and polysaccharide production, supporting their potential use in biotechnology and industrial applications.

• Klíčová slova
• Mucor circinelloides, Amino polysaccharides, Fatty acids, Fermentation, Lignocellulose,
• MeSH
• biomasa MeSH
• fermentace MeSH
• hydrolýza MeSH
• mastné kyseliny * biosyntéza   MeSH
• Mucor * metabolismus   růst a vývoj   MeSH
• polysacharidy * biosyntéza   MeSH
• smrk * metabolismus   chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• mastné kyseliny * MeSH
• polysacharidy * MeSH

BACKGROUND: Monitoring and control of both growth media and microbial biomass is extremely important for the development of economical bioprocesses. Unfortunately, process monitoring is still dependent on a limited number of standard parameters (pH, temperature, gasses etc.), while the critical process parameters, such as biomass, product and substrate concentrations, are rarely assessable in-line. Bioprocess optimization and monitoring will greatly benefit from advanced spectroscopy-based sensors that enable real-time monitoring and control. Here, Fourier transform (FT) Raman spectroscopy measurement via flow cell in a recirculatory loop, in combination with predictive data modeling, was assessed as a fast, low-cost, and highly sensitive process analytical technology (PAT) system for online monitoring of critical process parameters. To show the general applicability of the method, submerged fermentation was monitored using two different oleaginous and carotenogenic microorganisms grown on two different carbon substrates: glucose fermentation by yeast Rhodotorula toruloides and glycerol fermentation by marine thraustochytrid Schizochytrium sp. Additionally, the online FT-Raman spectroscopy approach was compared with two at-line spectroscopic methods, namely FT-Raman and FT-infrared spectroscopies in high throughput screening (HTS) setups. RESULTS: The system can provide real-time concentration data on carbon substrate (glucose and glycerol) utilization, and production of biomass, carotenoid pigments, and lipids (triglycerides and free fatty acids). Robust multivariate regression models were developed and showed high level of correlation between the online FT-Raman spectral data and reference measurements, with coefficients of determination (R2) in the 0.94-0.99 and 0.89-0.99 range for all concentration parameters of Rhodotorula and Schizochytrium fermentation, respectively. The online FT-Raman spectroscopy approach was superior to the at-line methods since the obtained information was more comprehensive, timely and provided more precise concentration profiles. CONCLUSIONS: The FT-Raman spectroscopy system with a flow measurement cell in a recirculatory loop, in combination with prediction models, can simultaneously provide real-time concentration data on carbon substrate utilization, and production of biomass, carotenoid pigments, and lipids. This data enables monitoring of dynamic behaviour of oleaginous and carotenogenic microorganisms, and thus can provide critical process parameters for process optimization and control. Overall, this study demonstrated the feasibility of using FT-Raman spectroscopy for online monitoring of fermentation processes.

• Klíčová slova
• Carotenoids, Infrared spectroscopy, Lipids, Partial least squares (PLS) regression, Process analytical technology, Raman spectroscopy, Real-time monitoring, Rhodotorula, Schizochytrium,
• MeSH
• biomasa MeSH
• fermentace MeSH
• glukosa metabolismus   MeSH
• glycerol MeSH
• karotenoidy metabolismus   MeSH
• Ramanova spektroskopie * metody   MeSH
• triglyceridy MeSH
• uhlík * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukosa MeSH
• glycerol MeSH
• karotenoidy MeSH
• triglyceridy MeSH
• uhlík * MeSH