By Robert Kozak (Atlantic Biomass Conversions, Inc.) Worldwide Importance of Protein Animal Feed
When I began working with sugar beet processors on our beet pulp biofuel sugar process, one of their first questions was, “Will there still be pulp available to sell for animal feed?”
I have to admit I did not appreciate the importance of that question when they first asked.
It took me a while to comprehend a fact that is overlooked by most people outside of animal husbandry and animal feed producers. Animal feed, and especially that containing high protein content, is becoming increasingly expensive. Why?
First, as the standard of living improves in countries, including China, the demand for meat has significantly increased. This has increased animal herds and feed lots, meaning animal feed demand has increased.
Second, animal diets higher in protein have been found by university and extension service studies to reduce indigestion caused by high carbohydrate loading and to improve meat quality since food additives can be reduced. Higher protein feeds are therefore being adopted by herd owners and feed lot operators because these improvements offer cost benefits -- provided protein feed cost increases are limited.
Third, much high protein animal feed is based on “rough” or bait fish such as menhaden. Because of the high demand for this fish protein, many of the “protein meal” fisheries have been fished out or are on the edge of crashing. One such fishery is the Chesapeake Bay menhaden.
Because of the precarious nature of many (if not all) of these populations, some governments have begun to restrict catches to preserve the populations. These restrictions, combined with the reduced catches from crashing populations have reduced yields while increasing prices.
Table 1 lists recent animal feed prices. And, to show their relative importance to biofuel production, the price of ethanol is included as well.
Table 1: Comparison of Animal Feed and Ethanol Prices
Animal Feed Prices: University of Missouri Division of Animal Sciences and Commercial Agriculture Program: 3/17/2011 By-Product Feed Price Listing
Ethanol: Spot Wholesale Price 4/12/11
|Animal Feed Type
|Distillers Dry Grain (DDG)
|Soyfeed SBM (soybean meal)
|Pork Blood Meal
|Choice White Grease
|Fish Meal (menhaden)
As you can see, the high protein animal feeds are more expensive than ethanol. Pork blood meal at $.45/lb is 15% more expensive than ethanol ($.39/lb), while fish meal at $.70/lb is 78% more than ethanol.
From a grower or processor’s standpoint, these prices say that not recovering biofuel biomass proteins is like throwing money away. For all people on the planet, recovering biomass proteins during biofuel production would be “Doing the Right Thing
That is the lesson I learned.
Biofuel Biomass Protein Quantities
The quantities and economic value of high protein feed that could be produced from advanced biofuel non-food or agricultural residues would be significant. Table 2 summarizes the results Atlantic Biomass Conversions has produced using our new enzymatic process that can both produce sugars for biofuel production and retain proteins for animal feed from beet pulp biomass, a residual from commercial sucrose production. The results are compared to a biofuel production process that would denature plant amino acids, making them unusable as animal feed, while it releases sugars for biofuel.
Table 2: Beet Pulp Biofuel Sugars and High Protein Content Animal Feed
||Protein Retaining Process
||Protein Non-Retaining Process
|Biofuel Sugar Price (per lb)
|Lbs Biofuel Sugars/Ton Pulp
|Biofuel Sugar Revenue/Ton Pulp
|Lbs Animal High Protein Feed/Ton Pulp
|High Protein Feed Price/lbs
|Increased Income %
|Decrease in Animal Feed Proteins (lbs)
By retaining plant amino acids, the income from the pulp used for high protein animal feed (estimated at halfway between medium value soyfeed and pork blood meal for this example) would increase per ton pulp revenue by 65%. This additional revenue would allow growers to offer biofuel sugars at a competitive price while continuing to practice good soil and nutrient retention techniques.
On the protein feed side of the equation, the process also retains 300 pounds/ton of residual beet pulp as high protein feed. Pulp currently processed in US plants would be able to produce an annual minimum of 150,000 tons of high protein feed while worldwide beet pulp supplies
could yield approximately 900,000 tons/year
Jonathan Mielenz of the Oak Ridge National Lab (“Fermentation of Soybean Hulls to Ethanol While Preserving Protein Value
,” Jonathan R. Mielenz, John S. Bardsley, Charles E. Wyman, Bioresource Technology
, Vol. 100, 3532-3539, 2009) calculated that a process that retains biomass proteins while producing ethanol from soybean hulls, which are also non-food agricultural residues, could produce 1.5 million tons/year of protein feed from the US soybean crop.
Corn ethanol producers are also familiar with feed proteins that are produced during ethanol production. They are called dried distiller’s grain (DDG), a medium protein feed ($.09-.10/lb) that is a byproduct of corn starch fermentation. Reuters reports http://www.commodities-now.com/reports/power-and-energy/5713-ethanols-overlooked-source-of-food-supply.html
that approximately 40 million short tons of DDGs are produced from the 4.95 billion bushels of corn set to be consumed by ethanol producers in the current grain marketing year.
In essence, by retaining the plant proteins for animal feed, most of the “food” portion of biofuel crops or agricultural residue is retained. Only the plant sugars, which many researchers say all animals should be cutting down on, are used for fuel. By following this path, biofuel production will actually add to the sustainability of worldwide agriculture.
What Biofuel Production Processes Can Retain Proteins?
The market demand and production opportunities for high protein animal feed argues strongly for the implementation of ONLY biofuel production systems that are able to retain plant produced proteins contained in the biomass. The question therefore becomes, what systems can retain the proteins for animal digestion and which ones cannot?
The US DOE classifies non-starch biomass (referred to as cellulosic) biofuel production systems into two general categories; 1) Thermochemical, and 2) Biochemical. Let’s see how plant proteins fare in each of them.
: As defined by US DOE, “The gasification process uses heat and may use a limited amount of oxygen to convert biomass into a synthesis gas (syngas), which consists primarily of carbon monoxide and hydrogen. These conversion processes include gasification [presence of oxygen] and pyrolysis [absence of oxygen].”
Simply stated, plant amino acids that comprise proteins are broken down into CO, H2
, and other gases when “using heat [2000
F or above] … to convert biomass into a synthesis gas.” Therefore, thermochemical biofuel production processes will not retain plant biomass proteins for animal feed
As defined by US DOE, “Biomass is broken down to sugars using either enzymatic or chemical processes and then converted to ethanol via fermentation.”
A biochemical process is also called the Sugar Platform
by DOE and may include non-fermentation processes that can convert plant sugars to biofuels other than ethanol.
This Biochemical Process is defined by US DOE as consisting of three steps:
: Biomass is made ready to be treated with enzymes,
: Biomass is enzymatically converted (hydrolyzed) to sugars, and
3. Biofuel Production
: Sugars are converted via fermentation or other biochemical processes to biofuels or fuel precursors.
The critical step for the retention of plant amino acids is pretreatment. If thermochemical pretreatments such as high temperature, high pressure, high acid treatments (low pH), or high basic treatments (high pH) are used (Harsh Pretreatment
) the structure of many plant amino acids can be degraded beyond the point they can be beneficially digested by domestic animal herds.
The key to a biochemical process that can retain plant proteins and produce biofuel sugars is therefore the use of Benign Pretreatment
Successful Benign Pretreatment Approaches
Jonathan Mielenz’s research team obtained their promising soybean hull results with a simultaneous saccacharification and fermentation (SSF) organism. This organism was able to produce enzymes that could release glucose from the hull cellulose and ferment it to ethanol. Plant proteins were retained at the end of the process. This entire process was performed without any thermochemical pretreatment.
In our work at Atlantic Biomass Conversions, we have developed a sequential enzyme approach that releases glucose from cellulose; arabinose and xylose (five-carbon sugars) from hemicellulose biomass; and galacturonic acid (a six-carbon sugar) from pectin biomass, without pretreatment. (Releasing hemicelluloses and pectin sugars is necessary since over 40% of most biofuel carbohydrate sources are not cellulose.) Tests of the remaining biomass showed that the proteins are retained.
Towards Food and Fuel Sustainability
Table 3 summarizes the ability of the different biofuel production technologies to produce both biomass sugars and retain plant proteins for animal feed.
Table 3: Products of Biofuel Production Systems
|Biofuel Production System
||Retains Plant Proteins
Therefore, since innovative enzymatic processes do exist that produce high yields of plant biomass sugars while also retaining plant proteins, commercialization of these, and other Benign Pretreatment technologies should be given high priority by both government and private funding sources.
From the investment side of the equation, the inclusion of high protein feed makes the bottom-line of all biofuel producers look much better.
Much more important, the implementation of biofuel production systems that retain most of the “food” portion of biofuel crops or agricultural residue would add to the sustainability of worldwide agriculture while reducing the need for non-renewable petroleum. This is “Doing the Right Thing
.” It should therefore be a top priority for all nations producing biofuels.
Editor’s note: The author is President of Atlantic Biomass Conversions, Inc. The opinions expressed are those of the author and should not be attributed to Advanced Biofuels USA, a nonprofit educational organization which advocates for the adoption of advanced biofuels as an energy security, military flexibility, economic development and climate change mitigation/pollution control solution. Our key tool for accomplishing this is our web site, www.AdvancedBiofuelsUSA.org, a one-stop-shop library for everyone from opinion-leaders, decision-makers and legislators to industry professionals, investors, feedstock growers and researchers; as well as teachers and students.