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Comment 6 for Comments for the LCFS Method 2A2B applications (lcfs2a2bcomments-ws) - 2nd Workshop.

First Name: Monica
Last Name: Hirsch
Email Address:

Subject: Molasses and sugar cane juice
We hereby respectfully disagree with CARBs recommendation for a new
pathway for Molasses Ethanol (ETHM004) with a CI of 14.93 g CO2e/MJ
and we kindly offer here our points of view and questions for your

The typical fermentation process to produce ethanol in a Brazilian
mill in the state of São Paulo with over 35 years of operation
(before Brazil’s Pro Alcool Program), consists of a mixture of
sugar molasses from the sugar factory and cane juice, coming
directly from the milling. We estimated that  50.5% of all ethanol
produced in Brazil Center South has the same origin (molasses) and
follow the same pathway (in parallel with different amounts of cane
juice, depending on the sugar mill) as the analyzed in the
“Molasses to ethanol” pathway from CARB. The amount of molasses
used, for any mill, is easily verified through the sugar

Note that molasses is essentially formed by fructose and glucose,
which do not crystallize, unlike sucrose, abundant in cane juice
and of simple crystallization. So the fermentation process to
produce ethanol in several similar units in Brazil as the presented
mill, actually happen from a mixture of the poor molasses from the
sugar milling with sugarcane juice, never from molasses alone. The
mixture of molasses and secondary sugarcane juice in the
fermentation occurs mainly for three reasons:

1 - The yeast strains used typically “prefers“ also sucrose to
glucose and fructose and the fermentation process is inefficient 
without sucrose, demanding higher fermentation vessels (higher
CAPEX), slower fermentation process  (higher risk of infection and
loss) converging to lower fermentation rates (lower return);
2 - Since molasses coming from the sugar factory is low in total
sugars (the sucrose was crystallized), assuming maximum efficiency
in the sugar production of which molasses is a by-product, it is
necessary to add the cane juice directly from the milling so even
before the start of fermentation (BRIX adjustment) at the risk of
the ineffectiveness of the fermentation process;
3 - Unlike standard distilleries in Central America and the
Caribbean that operate only from molasses and often are physically
and geographically separated from the unit that processes and
produces sugarcane, typical plants in the state of São Paulo,
Brazil are pre-1980 and although they were born only to make sugar
have expanded its crushing capacity and processing along the last
decades. Thus there are no known cases of plants in the state of
São Paulo that produce ethanol exclusively from molasses since,
even ignoring items 1 and 2 above, its sugar factories are
insufficient to process all the juice immediately. Such plants can
surely produce ethanol from molasses, but only a tiny fraction of
the total ethanol produced in that unit.

Accepting this pathway submitted, CARB is agreeing that the mill’s
production mix (between sugar and ethanol) will be used to define
the CI for the pathway for molasses only production but in practice
it is not happened. Will you consider two pathways for the same
ethanol product?

We would be glad to discuss this further with CARB and present
additional evidence if necessary. We hope CARB will consider this
comment and revert its position on this matter.


Original File Name:

Date and Time Comment Was Submitted: 2014-01-08 10:55:15

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