March 19, 2006

BIO Panel supports Cellulosic Ethanol

As reported by Green Car Congress, the Biotechnology Industry Organization (BIO) sponsored a panel presentation in Washington, DC to discuss processes used to convert cellulosic feedstocks into sugars preparatory to fermenting into ethanol.

Supporting cellulosic ethanol is a good thing. However, there are processes other than those discussed by the panel that should be considered in any discussion about bioconversion of cellulosic feedstock. Noticably missing was BRI Energy, LLC which employs syngas fermentation to convert biomass to ethanol.

The companies that participated in the panel use enzymatic hydrolysis which involves developing (to date) expensive enzymes to break down the feedstock into sugars before using conventional fermentation processes to distill the sugars to ethanol. The problem I see with that is that: 1) each feedstock requires enzymes customized for it, 2) the feedstock cannot be blended and 3) the process takes a long time (days).

BRI Energy employs a simpler and more efficient conversion process. It gasifies the feedstock which means that the biomass can be pure or blended. The gasification step generates heat (which can be used to co-generate electricity). The now gasified syngas, when cooled, can then be scrubbed and bio-converted to ethanol by feeding it to anerobic bacteria that eats up the gas and secretes ethanol in a closed fermenting chamber. The process takes about 7 minutes. Zero emissions with benign purge and ash.

I believe BIO is right - cellulosic ethanol is the way to go. But they should seat syngas fermentation technology on the panel.


BIO Pushes for Cellulosic Ethanol
17 March 2006
Cellulase enzymes will play a critical role in the enabling of the production of cellulosic ethanol.

BIO, the Biotechnology Industry Organization, organized a panel in Washington this week to describe the industrial biotechnology processes that enable large-scale production of cellulosic ethanol from biomass such as crop waste and switch grass. The panel included representatives from biotech and biofuel firms Diversa, Novozymes and Abengoa Bioenergy, as well as BIO itself and the Natural Resources Defense Council (NRDC).

Panelists at the event described how industrial biotechnology—called the third wave in biotechnology innovation—is using novel biotech tools to identify or improve enzymes from microbes for use in converting the hard, fibrous content of plants, primarily cellulose and lignin, to sugars.

The resulting sugars can then be fermented by biotech-improved bacteria to make ethanol transportation fuel or biobased plastics. Recently completed research on enzymes makes possible large-scale production of cellulosic ethanol from dedicated energy crops—such as switch grass—or crop wastes such as corn stover and wheat straw or rice straw at a cost competitive with that of petroleum-based fuels.

Industrial biotech is the enabling technology that will allow farmers to harvest two crops from every field—a food crop and a biomass crop for fuel production. Biotech breakthroughs mean that the nation’s breadbasket could also become the energy fields of the United States. The question is not when, but how soon this will happen.

—Brent Erickson, BIO EVP for industrial and environmental biotechnology



Robert Rapier said...

Hi Scott,

I worked on cellulosic ethanol in graduate school. I agree that if ethanol is to have a future, that is the way to go. Grain-based ethanol will never make it on its own. I just wrote about the truth behind grain-based ethanol in my blog:

C. Scott Miller, EDP said...

I think you were on the right track with your thesis.

What do you know about syngas fermentation and the use of bacteria to convert the syngas into ethanol and/or hydrogen, and water? BRI Energy has built a pilot plant in Fayetteville, ARK using an anaerobic bacteria to convert syngas gasified from a variety of cellulosic feedstock. They are primed to begin construction on a commercial scale facility.

If you haven't checked out their process, please do. You evaluation of their technology against other techniques for biomass conversion would be interesting to me.

Robert Rapier said...


I know that when we were doing fermentations, gas by-products were always a "problem". Mostly we got methane, but some syngas as well. Had we been trying to make syngas, we could have probably selected "bugs" that were good at that. So it is definitely feasible. I just don't know how high you can push the conversion.

I am going to be addressing some alternate technologies in some of the essays I have planned. I will look into BRI.


Robert Rapier said...

Hi Scott,

I just opened up the link to BRI. I thought that name sounded familiar. We talked about Gaddy's research quite a bit in graduate school. I am pretty sure my research advisor, Mark Holtzapple, collaborated with him some.

Knowing a little something about this kind of process, I think I know where the pitfall will be. As live microorganisms convert biomass into ethanol, their growth rate slows as ethanol, carboxylic acids, etc. build up. The trick is getting a high enough ethanol concentration to make distillation worthwhile. When I was doing this, you needed something better than 3% ethanol in water to make the energy break even. In other words, at that point the energy you put in is about equal to what you get out from the ethanol. The problem is that at 3% ethanol, the bugs start to die. That is what the advantage is of using enzymes. They don’t die.

But all of these ethanol processes suffer a similar problem. Every ethanol process, no matter the type or specific process, has the deal with the problem of getting all that water out. This consumes most of the energy content that you end up with, which is why the energy balance is poor. Ultimately, biodiesel would be so much better. It has almost twice the energy value per gallon, and you don't use up all the energy getting water out of it. I am going to write something up on it next.


C. Scott Miller, EDP said...

Since you have read the BRI Energy site, you will notice two well-respected energy and ethanol engineering companies, Parsons Corp. and Katzen International Inc., are involved in technology evaluation and support to scale up the pilot program to commercial viability.

In 2005, the Parsons Company conducted a technology evaluation of the BRI Energy process and confirmed:
• Technologic viability of BRI’s biologic approach to produce ethanol from carbon based synthesis gas.
• Evaluation of the Consutech (gasification) equipment as a reasonable technological solution for the production of synthesis gas for the BRI process.
• Technologic viability of the fermentation equipment and approach.
• Technologic viability of the distillation equipment and approach developed by Katzen.

Their evaluation also states that “the BRI process has sufficient waste heat to produce anhydrous ethanol without added energy costs. The process that KATZEN is currently employing in the majority of its ethanol projects, which will also be employed in the proposed BRI projects, reduces the distillation energy demand by approximately 30 – 40 percent. A recently published paper supports the ethanol concentration versus distillation energy efficiency relationship based upon conventional distillation / dehydration technology being employed in many
of today’s ethanol plants.”*

*“Recovery of Volatile Products from Dilute High-Fouling Process Streams” by Philip Madson and David Lococo, Published in Applied Biochemistry and Biotechnology, Vol. 84-86, 2000, Humana Press Inc.

Robert Rapier said...

It will be interesting to see how this plays out. Gaddy has been in this business a long time. If that nut can be cracked, he can probably crack it. I hope they can scale up the process. They must be counting on burning the unconverted biomass to provide some of the distillation energy. Any reduction in distillation energy demand is important, because that is what hurts the energy balance the most.

C. Scott Miller, EDP said...

Keep in mind that the feedstock for this bioconversion process is biomass in the broadest sense of the word - including even auto shredding residue (ASR) and MSW. Clean disposal of waste and reduction of greenhouse gases carries an additional social value that could be considered as important as the balanced generation of energy in certain settings (Detroit and L.A. for example). And decentralized location of processing facilities could save transport cost of both waste and energy, while reducing pollution.