Quantification of lycopenes in processed Polymorphospora lycopeni using Raman spectrometry.

Area of Science:

• Microbiology
• Spectroscopy
• Biotechnology

Background:

• Lycopene, a valuable carotenoid, is crucial for microbial applications.
• Quantifying intracellular lycopene in strains like Polymorphospora lycopene A560 is challenging due to filamentous morphology and spectral interference.
• Existing methods require laborious extraction and are time-consuming.

Purpose of the Study:

• To develop a rapid, reliable Raman spectroscopy-based method for intracellular lycopene quantification.
• To optimize sample preparation for reduced spectral variability and interference.
• To enable high-throughput screening of carotenoid-producing microbial strains.

Main Methods:

• Developed a Raman spectroscopy method for lycopene quantification in Polymorphospora lycopene A560.
• Integrated mechanical homogenization with TiO₂-assisted sample preparation.
• Employed Partial Least Squares (PLS) regression using characteristic Raman peaks (1006, 1156, 1523 cm⁻¹).

Main Results:

• Achieved significantly reduced spectral variability (CV < 8%) compared to unoptimized methods (58%).
• PLS regression model demonstrated high predictive accuracy (R² = 0.93, RMSECV = 3.60 mg/g).
• Method is 10-fold faster than spectrophotometry (3 min/sample) and identified high-yield mutants (42.05 mg/g dry biomass) with 95% Bland-Altman agreement.

Conclusions:

• The optimized Raman spectroscopy method provides a robust platform for rapid intracellular lycopene quantification.
• This approach eliminates the need for laborious extraction, enhancing efficiency in carotenoid bioproduction.
• The method facilitates high-throughput strain screening for optimizing carotenoid yields.