Assessment of Biotechnologically Important Filamentous Fungal Biomass by Fourier Transform Raman Spectroscopy.

Simona Dzurendová,Dana Byrtusová,Achim Kohler,Martin Szotkowski,Valeria Tafintseva,Volha Shapaval,Ivana Márová,Boris Zimmermann

doi:10.3390/ijms22136710

Abstract

Oleaginous filamentous fungi can accumulate large amount of cellular lipids and biopolymers and pigments and potentially serve as a major source of biochemicals for food, feed, chemical, pharmaceutical, and transport industries. We assessed suitability of Fourier transform (FT) Raman spectroscopy for screening and process monitoring of filamentous fungi in biotechnology. Six Mucoromycota strains were cultivated in microbioreactors under six growth conditions (three phosphate concentrations in the presence and absence of calcium). FT-Raman and FT-infrared (FTIR) spectroscopic data was assessed in respect to reference analyses of lipids, phosphorus, and carotenoids by using principal component analysis (PCA), multiblock or consensus PCA, partial least square regression (PLSR), and analysis of spectral variation due to different design factors by an ANOVA model. All main chemical biomass constituents were detected by FT-Raman spectroscopy, including lipids, proteins, cell wall carbohydrates, and polyphosphates, and carotenoids. FT-Raman spectra clearly show the effect of growth conditions on fungal biomass. PLSR models with high coefficients of determination (0.83–0.94) and low error (approximately 8%) for quantitative determination of total lipids, phosphates, and carotenoids were established. FT-Raman spectroscopy showed great potential for chemical analysis of biomass of oleaginous filamentous fungi. The study demonstrates that FT-Raman and FTIR spectroscopies provide complementary information on main fungal biomass constituents.

Highlights

Filamentous fungi have been commercially used in biotechnology for over a century, creating a range of products from organic acids, enzymes, and oleochemicals to antibiotics, statins, and steroids for applications in the food, pharma, and chemical industry [1,2,3].Some of the most important filamentous fungal cell factories, such as Mortierella, Mucor, Rhizopus, and Umbelopsis genera, belong to the Mucoromycota taxon
The study, conducted on six strains of Mucoromycota filamentous fungi, demonstrates that quality Raman spectra of fungal biomass can be acquired by Fourier transform (FT)-Raman spectroscopy
FT-Raman spectra are rich in chemical information and provide data on all main chemical constituents of fungal biomass, including acylglycerol lipids, proteins, cell wall carbohydrates, and polyphosphates

Summary

Introduction

Filamentous fungi have been commercially used in biotechnology for over a century, creating a range of products from organic acids, enzymes, and oleochemicals to antibiotics, statins, and steroids for applications in the food, pharma, and chemical industry [1,2,3].Some of the most important filamentous fungal cell factories, such as Mortierella, Mucor, Rhizopus, and Umbelopsis genera, belong to the Mucoromycota taxon. Mucoromycota have gained interest due to their versatile metabolism that enables fermentation process on a wide range of feedstock, such as waste and rest materials [4,5]. Fermentation is the most complex individual process within biotech-manufacturing and it poses a number of challenges related to productivity and quality. Process monitoring is still dependent on a limited number of standard sensors for pH, temperature, and gases, while the critical process parameters, such as biomass, product and substrate concentrations, and compositions, are rarely assessable on-line. There is a need for rapid methods that provide detailed chemical information for bioprocess monitoring and optimization. Process optimization and monitoring will greatly benefit from advanced spectroscopy-based sensors that will enable real-time monitoring and control of bioprocesses

Methods

Results

Conclusion