Title:
Production of Microbial Oils from Sugar Cane Molasses: Process Optimization and Scale-up
Author(s):
Albergo, R., Bianco, L., Caporusso, A., Limonti, C., Valerio, V., Viola, E., De Bari, I., Rizzo, C., Rapone, I.
Document(s):
Paper
Poster
Abstract:
Molasses, a viscous by-product of the sugar industry, is a carbon-rich substrate containing approximately 50–55% total sugars, including sucrose, glucose, and fructose. Besides its sugar content, it also contains amino acids, phenolic compounds, and inorganic salts, making it a nutrient-rich feedstock. Traditionally considered an industrial effluent due to its high biochemical and chemical oxygen demand (BOD and COD), molasses is now being revalorized for sustainable biotechnological applications. This study aimed to develop an efficient and scalable process to produce microbial oils (single-cell oils, SCOs) using molasses as a primary carbon source. SCOs are lipids produced by microorganisms such as yeasts and fungi, offering a sustainable alternative to conventional oils for biofuel, food, and pharmaceutical applications. An initial screening of several oleaginous yeasts was conducted to identify the most suitable strain for lipid accumulation despite unfavourable growth conditions (low C/N molar ratio due to high nitrogen content of the molasses). Among the tested strains, Lipomyces tetrasporus DSM70314 showed the highest performance, efficiently consuming sucrose without pretreatment and accumulating intracellular lipids up to 30% of its dry biomass. The process was further optimized in bench-scale and pilot-scale bioreactors, exploring various substrate compositions, feeding strategies, and aeration conditions. The highest oil yield was obtained using a mixture of molasses (10%) and crude glycerol (5%) under fed-batch conditions (pO2 40%, 28.°C, pH 6). Scaling up to a 50.L bioreactor using a constant tip speed approach resulted in a dry biomass yield of 23.2.g/L, with an oil content of 30–40%. Chemical analysis revealed a triglyceride-rich oil (=90%), predominantly composed of oleic (40%) and stearic acid (20%), showing a composition like vegetable oils and indicating its potential suitability for use in Ecofining™ plants.
Keywords:
crude glycerol, single cell oils, lipomyces tetrasporus, sugarcane molasses, bioreactor scale-up
Topic:
Biomass, Bio-based Products and Bioenergy Integration
Subtopic:
Biomass use in biorefineries
Event:
33rd European Biomass Conference and Exhibition
Session:
3CV.4.18
Pages:
522 - 526
ISBN:
978-88-89407-25-7
Paper DOI:
10.5071/33rdEUBCE2025-3CV.4.18
Price:
FREE
