Single cell oil production integrated to a sugarcane-mill: Conceptual design, process specifications and economic analysis using molasses as raw material

• Rhodotorula glutinis lipid production with low-cost raw sugarcane molasses was accessed.
• A new substrate feeding strategy for at high-cell density was setting up in bench scale bioreactor.
• A Process Flow Design (PFD) integrated to a typical Brazilian sugar mill was proposed according to fermentation experiments.
• Performed economic analysis provided data for discussion on strategic equipment that can facilitate the viability to the process.

This study aimed to assess the single-cell oil production integrated to a sugarcane-mill and molasses as main raw material. Rhodotorula glutinis lipid production with low-cost raw sugarcane molasses was accessed. The envisage process relies in an optimized sugarcane molasses culture media in a fed-batch strategy to achieve a high-cell density high-lipid cell content. A Process Flow Design (PFD) integrated to a typical Brazilian sugar mill was proposed according to fermentation experiments. Performed economic analysis provided data for discussion on strategic equipment that can facilitate the viability to the process. Typical results of established protocol were total biomass concentration 62.25 g l−1, lipid productivity 0.42 g l−1 h−1, sugar conversion yield to lipids 0.21 g of lipid g−1 of total reducing sugar. Microbial lipid production and defatted biomass plant production was proposed at a nominal capacity of respectively 16,720 ton and 21,600 ton per year, running 8300 h per year. The projected selling prices of these products were US$ 1,300.00/ton of lipid and US$ 500.00/ton of defatted yeast. It was demonstrated that the industrial plant was potentially attractive when capital investment cost was decreased with the use of low cost epoxy-lined carbon steel stirred bioreactor. In this alternative, the internal rate of return (IRR) will be 24.61% leading the NPV (at 7% interest rate) of US$ 67,797,000/year (before taxes).