Valorization of microalgae into 5-hydroxymethylfurfural by two-step conversion with ferric sulfate

Area of Science:

• Biomass Conversion
• Renewable Energy
• Green Chemistry

Background:

• Microalgae are sustainable feedstocks for biofuel and chemical production.
• Thermochemical conversion offers a pathway for biomass valorization.
• Efficiently producing sugars and 5-HMF from microalgae is crucial for biorefineries.

Purpose of the Study:

• To optimize the thermochemical conversion of Chlorella sp. microalgae for sugar production.
• To develop a two-step thermochemical process for producing 5-hydroxymethylfurfural (5-HMF) from microalgae.
• To evaluate ferric sulfate as a catalyst for microalgal biomass conversion.

Main Methods:

• Statistical optimization using Box-Behnken design for sugar yield.
• Two-step thermochemical conversion: first for sugars, second for 5-HMF.
• Utilized ferric sulfate as a catalyst in the first conversion step.

Main Results:

• Optimized conditions yielded 86.46% sugar (68.32% glucose) at 155°C with 5% biomass and 0.6 g-catalyst/g-biomass.
• Maximum 5-HMF yield of 37.23% achieved in the second step at 170°C for 60 min.
• Ferric sulfate demonstrated effectiveness as a catalyst for microalgal conversion.

Conclusions:

• Microalgae are viable biomass feedstock for producing biosugars and platform chemicals.
• Ferric sulfate is an available and effective catalyst for this conversion process.
• The developed two-step thermochemical conversion is a promising route for microalgal valorization.