(582c) Fatty Acid Alkyl Ester Recovery From Intracellular Triacylglycerides (TAGs) – Development of a Single Step Reactive Extraction and Separation Process

Fatty
acid alkyl ester recovery from intracellular triacylglycerides (TAGs) ?
development of a single step reactive extraction and separation process.

A
single-step reactive extraction method was examined for recovery of cellular lipids
(such as free fatty acids as well as mono-, di- and
tri- glycerides). In this process, biomass is treated with acidified alcohols
(such as methanol or ethanol) at elevated temperatures to produce
transesterified lipids (alkyl esters such as fatty acid methyl esters or
FAMEs). The FAMEs can then be used directly as biodiesel, or can be further
processed to recover high value products such as omega-3 fatty acids.

In this study,
we have examined the kinetics of FAME recovery as influenced by temperature
(60-100 °C) as well as acid (1-5% (v/v)) and biomass concentrations (6.6-25%
(w/v)). Rates of reaction increased with temperature in accordance with the
Arrhenius equation. Based on the fundamental acid-catalyzed transesterification
mechanisms, a kinetic expression was derived. Rate data for reactions with
various acid and biomass concentrations were found to be in excellent agreement
with this model. An interesting observation that resulted from this study was
that under appropriate conditions, the FAMEs separated out from the reaction
mixture as a distinct light phase that could be easily removed. Further, the
heavy phase containing acidified methanol could be reused for reacting more
biomass. Overall, this process enables easy recovery of transesterified lipids
by a one-step process that eliminates the need for toxic solvents and their
expensive recovery. Process design is also simplified since reaction kinetics are described by rate expressions derived from first
principles. Experimental results and an economic
analysis of the process will be presented.