New Technologies for Single-Cell Protein

CelloFuel Strategy - What do we do?

The world’s largest yeast companies, including LeSaffre, AB Mauri, Angel Yeast and Lallemand, produce yeast that is too expensive to compete with soy protein for animal feed. We’re developing technologies for reducing the cost of producing yeast so that it competes with soy protein in fish feed and animal feed. Our solution is to use new technologies to significantly reduce the CAPEX and OPEX to produce yeast from dry-grind corn.

More than 50% of the cost of producing yeast is due to the cost of the substrate you start with. It’s less expensive to grow yeast on hydrolyzed sugars from dry-grind corn than any other substrate that we’ve found. Note however that our technologies can produce yeast from any kind of grain, especially wheat, but wheat is more expensive than corn because it’s used to make bread (the gluten makes dough where corn doesn’t). In countries with a surplus of low-cost wheat, it can be used to produce yeast with our technologies.

Our focus is on innovative, cost-effective technologies for producing single-cell protein (yeast) for fish feed and animal feed at a lower cost than soy protein. Yeast is also a much healthier fish feed and animal feed than soy protein.

We are licensing these patents, technologies and reference designs to customers who have access to large amounts of inexpensive corn and markets for fish feed and/or animal feed. Our target markets are located worldwide, particularly in the USA, Russia, India, China, Argentina and Mexico.

Our key patent is a bacterial contamination control technique involving limiting nickel in the fermentation broth while using only urea as the nitrogen source for yeast. Bacteria can’t use urea as a nitrogen source without nickel as a cofactor, thus preventing bacterial growth by limiting nickel. Yeasts only need biotin and don’t need nickel to use urea as a nitrogen source. Using this patent makes it possible to use evaporative cooling to reduce the cost of producing yeast, since otherwise contamination from cooling air would be a problem.

Our key reference design for making yeast is a containerized fermenter using a rotating drum bioreactor made of corrugated HDPE which doesn’t leach nickel like stainless steel does. This reference design uses evaporative cooling instead of plate heat exchangers. This design allows unattended operation for months at a time because there’s no need to clean plate heat exchangers.

These containerized fermenters use standard 20 ft and 40 ft shipping containers. They are designed for stacking 4 high when operating, transporting by train or truck, and rapidly constructing into large systems.

Contamination Control

Bacterial contamination is often the biggest technical problem when fermenting ethanol or growing yeasts at an industrial scale.

We’ve invented a patented technology for preventing contamination by using urea as the sole nitrogen source along with ensuring that the nickel concentration is less than 1 mg/kg. No acid wash or antibiotics are needed to prevent 100% of all bacterial contamination.

We are also using fed-batch feeding of urea with simultaneous saccharification and fermentation (SSF) of starch, in a continuous process, which results in a very high fermentation rate with no bacterial contamination.

This technique allows fermentation at pH 4 to pH 7 without bacterial contamination.

PCT Patent WO2024092285A2

U.S. Patent No. 12,297,423

U.S. Patent App. No. 19/202,827, filed May 8, 2025

Rotating Drum Bioreactor

We are building a rotating drum bioreactor (RDB) that takes advantage of our contamination control patents.

This is designed for aerobic growth of yeast using hammer-milled corn in a year-round process.

The building block of this RDB fermenter is a corrugated HDPE pipe which enables us to build large, containerized, stackable fermenters for less than $1000/m3, while traditional fermenters cost more than $15,000/m3. A 2 m x 5 m x 5 mm stainless steel 316L drum costs more than $9000 and the same sized HDPE drum costs less than $1000. The operating cost of our RDB fermenters is also much lower than traditional submerged fermentation.

These RDB fermenters use a continuous process using granular starch hydrolyzing enzymes (GSHE, a combination of glucoamylase and alpha-amylase) with hammer-milled corn and using simultaneous saccharification and fermentation (SSF) at 38 C with Candida utilis yeast (synonymous with Cyberlindnera jadinii). To speed up the process we do yeast recycling and enzyme recycling.

These RDB fermenters don’t use heat exchangers to remove the heat of fermentation, but instead use evaporative cooling , which reduces CAPEX and OPEX as well as eliminating the expense of cleaning plate heat exchangers.

These RDB fermenters are self-cleaning from the abrasion of rotating ground corn.

The cost of drying the yeast is low because there is only about 50% water content in the final slurry.

These RDB fermenters are containerized and are fully automated.

Healthier than Soy Protein

Our rotating drum bioreactor produces yeast that is significantly healthier than soy protein, at a competitive price.

Growing soybeans uses many unhealthy herbicides and pesticides, and these enter the food chain through soy protein in animal feed.

Soy also contains many anti-nutritional compounds that are unhealthy in fish feed and animal feed.

Yeast has been shown to be much healthier than soy protein and has a better balance of amino acids than soy protein. It is also more sustainable, needing less land than soybeans.

Our process can produce yeast which has been shown to be very nutritious for fish and chicken, and thus makes a more valuable feed for fish and chicken.

The base price of dried fodder yeast varies by country, with higher-cost economies like Japan and the U.S. at the top end.

The reduced CAPEX and OPEX of our rotating drum bioreactor along with producing a more nutritious animal feed than soy protein results in a cost-effective product.

Yeast from Corn

Our rotating drum bioreactor can cost-effectively produce protein-rich yeast from dry-grind corn.

These are hydrolyzed to glucose by granular starch hydrolyzing enzymes (GSHE enzymes, also called no-cook enzymes) and the glucose that is released is used to grow yeast at the same time (Simultaneous Saccharification and Fermentation, SSF).

This is the lowest-cost source of sugars for growing yeast aerobically. These same enzymes are used by POET (one of the world’s largest bioethanol makers) to make ethanol using their BPX process. POET makes ethanol anaerobically while we’re making yeast aerobically, but we’re using the same SSF process as POET.

The energy cost of drying this yeast is very low since the moisture level of solid-state fermentation is only about 50% moisture.

Candida utilis yeast is Generally Recognized As Safe (GRAS) and is approved worldwide for human consumption, fish feed and animal feed. It is currently sold worldwide by Lallemand as Torula yeast, is used as a flavoring ingredient and has been safely used in human, fish and animal feed since the 1930’s.

We believe we can cost-effectively increase the omega-3 fatty acid content of Candida utilis by using extracellular lipase enzymes and extracellular phytase enzymes secreted by Candida utilis during growth so that Candida utilis can metabolize the corn oil from the hammer-milled corn.

Using Yeast in Animal Feed

Yeast is very healthy when consumed by fish, chicken, pigs and humans. The feed conversion ratio (how many kg of feed it takes per kg of weight gain) is between 1.0 and 2.0 for fish, between 1.7 and 2.0 for chicken, between 2.5 and 3.5 for pigs and between 6.0 and 10.0 for cattle (so feeding yeast to cattle isn’t very efficient).

About 140 million tons of chicken (poultry) are raised per year, 110 million tons of pigs are raised per year, and 90 million tons of fish are raised in aquaculture per year, so the market for yeast in fish feed and animal feed is very large. The size of the worldwide market for nutritional yeast for human consumption is estimated at less than 10,000 tons per year.

There are two important aspects of the health effects of yeast in fish feed and animal feed - whether it provides essential amino acids for fish and animal growth and whether there is a good balance of essential fatty acids in fish and animals.

Essential Amino Acids

Essential amino acids are amino acids that fish, chicken, pigs and humans cannot synthesize on their own and must be obtained through the diet. There are nine essential amino acids:

  1. Histidine - Supports growth, tissue repair, and histamine production.

  2. Isoleucine - Aids in muscle metabolism, energy regulation, and hemoglobin production.

  3. Leucine - Promotes muscle protein synthesis and tissue repair.

  4. Lysine - Involved in protein synthesis, hormone function, and enzyme production.

  5. Methionine - Supports detoxification, metabolism, and sulfur-containing compound production.

  6. Phenylalanine - Precursor for neurotransmitters like tyrosine, dopamine, and norepinephrine.

  7. Threonine - Essential for collagen, elastin, and immune function.

  8. Tryptophan - Precursor for serotonin and melatonin, aiding mood and sleep regulation.

  9. Valine - Supports muscle growth, energy production, and tissue repair.

Arginine is also an essential amino acid in animal feed for fish, chicken and pigs.

Candida utilis yeast is complete in all essential amino acids and is prototrophic (self-sufficient) in biotin and all B-vitamins (except for vitamin B12). Depending on the growth environment, yeast can be deficient in methionine and/or lysine and sometimes needs to be supplemented in fish, chicken, pig and human diets.

Synthetic amino acids (e.g., L-lysine, DL-methionine, L-threonine) are commonly added to diets containing yeast to correct deficiencies, especially in chicken and pigs. This is economically viable and reduces reliance on traditional protein sources like fishmeal or soybean meal.

Soy protein is also deficient in methionine and lysine and provides fewer B-vitamins than yeast.

Essential Fatty Acids

Essential fatty acids are fatty acids that the human body cannot produce and must be consumed through food. There are two essential fatty acids:

  1. Alpha-Linolenic Acid (ALA) - An omega-3 fatty acid, crucial for heart health, brain function, and reducing inflammation. Found in flaxseeds, chia seeds, walnuts, hemp seeds, and certain oils (e.g., flaxseed oil).

  2. Linoleic Acid (LA) - An omega-6 fatty acid, important for skin and hair health, growth, and cell membrane function. Found in vegetable oils (e.g., sunflower, safflower, corn), nuts, seeds, and processed foods.

The human body uses ALA and LA as precursors to synthesize other fatty acids, like EPA and DHA (omega-3s), though conversion is limited. A balanced intake of omega-3 and omega-6 fatty acids is important to avoid inflammation from excessive omega-6 consumption.

Candida utilis produces both of these essential fatty acids, especially with solid-state fermentation because of the increased oxygen transfer rate. The enzymes that produce these fatty acids are present in Candida utilis (but not in S. cerevisiae) and need oxygen to desaturate oleic acid to linoleic acid (omega-6) and desaturate linoleic acid (omega-6) to alpha-linolenic acid (omega-3). Since the linoleic acid (omega-6) from corn oil is metabolized by Candida utilis, the CuFAD3 enzyme in Candida utilis can desaturate it to alpha-linolenic acid (omega-3).

Soy protein has a large excess of omega-6 fatty acids, is deficient in omega-3 fatty acids and contains no EPA or DHA. Soy protein in fish feed and animal feed results in fish and animals with too much omega-6 fatty acid content, which is ultimately unhealthy for humans. Feeding fish and animals yeast containing omega-3 fatty acids is much healthier than soy protein.

Anti-Nutritional Factors (ANFs) in Soy Protein

Soy protein contains many anti-nutritional compounds that are unhealthy in the diet of fish and animals. This includes trypsin inhibitors, lectins, oligosaccharides, phytic acid, saponins, soy antigens, isoflavones and tannins.

Carnivorous fish (e.g., salmonids, shrimp) are particularly sensitive to soy ANFs due to their limited ability to digest plant-based carbohydrates and their sensitive gastrointestinal systems. High soy inclusion (e.g., >30% soybean meal) often leads to enteritis, reduced growth, and altered gut microbiota.

Young monogastric animals (piglets, chicks, calves) are most affected due to immature digestive systems. For example, galacto-oligosaccharides and trypsin inhibitors are critical for piglets, while antigens and lectins are problematic for calves. Poultry are sensitive to trypsin inhibitors and oligosaccharides, leading to diarrhea and reduced growth.

Yeast does not contain any of these anti-nutritional factors and results in healthier fish, chickens and pigs when yeast is included in their feed.

Economics of Producing Yeast from Dry-grind Corn

More than 50% of the cost of producing yeast is due to the cost of the substrate you start with. It’s less expensive to grow yeast on hydrolyzed sugars from dry-grind corn than any other substrate that we’ve found.

Wheat is also relatively inexpensive to grow yeast, but it’s the main crop used worldwide for human consumption. It’s more expensive to produce yeast from sugars from sugarcane and sugar beet, both molasses and raw sugar. It’s more expensive to produce yeast from sugar beet pulp, lactose in waste whey, glycerol, lignocellulose hydrolysate, sulfite pulp liquor, and dilute acid hydrolysate of wood. Waste water treatment makes it more expensive to make yeast with submerged fermentation too. We’ve extensively analyzed the economics of all of these substrates using the most advanced AI - Grok 4 - and the conclusion is always the same, that dry-grind corn is the least expensive substrate for producing yeast.

Economic viability hinges on low capital and operating costs from the RDB design, inexpensive substrates, and high-value single-cell protein (SCP) for feeds.

  • Capital Expenditures (CAPEX): RDB construction at <$1,000/m³ significantly undercuts traditional fermenters (>$15,000/m³), potentially reducing overall plant CAPEX by 50-80% for a modular setup.

  • Operating Expenditures (OPEX):

    • Substrate Costs: Dominant factor (35-62% of total costs in SCP production).

      At $150/MT corn and ~0.385 MT SCP/MT corn (based on 70% starch, 1.1 g glucose/g starch, 0.5 g biomass/g glucose), substrate cost is ~$390/MT SCP.

    • Other OPEX: Enzymes, urea, energy for rotation/cooling, and drying. Evaporative cooling and self-cleaning eliminate heat exchanger maintenance (~$0.05-0.10/kg SCP in traditional systems). Drying from 50% moisture is cheaper than from 90% in submerged fermentation. Total non-substrate OPEX estimated at $200-300/MT SCP.

    • Labor and Utilities: Unattended operation minimizes labor; energy for rotation/aeration is low in containerized units.

  • Yields and Revenue: SCP yield ~385 kg/MT substrate with 45-50% protein.

    Market price for fodder yeast mixed with DDGS (dried residual after hydrolysis of starch in corn) varies by region (e.g., $500-1,000/MT for animal feed, competing with soy meal at ~$400/MT with 45% protein).

    On a protein basis, SCP at ~$800-1,000/MT protein vs. soy ~$890/MT protein, with SCP offering better nutrition for fish and animal feed.

    Potential revenue: $600-800/MT SCP sold.

  • Profitability:

    Substrate Cost (/MT SCP) $390 (corn at $150/MT)

    Total Production Cost (/MT SCP) $600-700

    CAPEX (/m³ fermenter) <$1,000

    Break-even Price (/MT SCP) $550-650

    ROI (5-year, 50k MT/year plant) 20-30%

    The RDB's low costs could yield margins of 20-40%, especially in high-feed-demand regions.

In summary, the RDB approach appears economically competitive for feed markets, with cost advantages enabling profitability at scale, though full commercialization would require pilot validation.

Target Markets

Our target markets are where there is a large amount of corn and wheat for making yeast and a large market for fish feed and/or animal feed.

The United States produces 399 MMT/y (million metric tons per year) of corn, 53 MMT/y of wheat and has a large market for animal feed.

China produces 295 MMT/y of corn, 142 MMT/y of wheat and has a large market for fish feed and animal feed.

Argentina produces 53 MMT/y of corn and has a large market for animal feed.

Russia and Ukraine together produce 45 MMT/y of corn, 106 MMT/y of wheat and have a large market for fish feed and animal feed

India produces 42 MMT/y of corn, 118 MMT/y of wheat and has a large market for fish feed and animal feed.

Mexico produces 25 MMT/y of corn and has a large market for animal feed.

The world price for corn and wheat is currently about $200/MT. When hydrolyzed, sugars from corn are significantly less expensive than sugarcane or sugar beet sugars.

Who are we?

Hamrick Engineering was founded in 2013 by Edward B. Hamrick.

Edward (Ed) Hamrick graduated with honors from the California Institute of Technology (CalTech) with a degree in Engineering and Applied Science. He worked for three years at NASA/JPL on the International Ultraviolet Explorer and Voyager projects and worked for ten years at Boeing as a Senior Systems Engineer and Engineering Manager. Subsequently, Ed worked for five years at Convex Computer Corporation as a Systems Engineer and Systems Engineering Manager. Ed has been a successful entrepreneur for the past 25 years.

Alex Ablaev, MBA, PhD is Sr. Worldwide Business Developer. Alex previously worked for Genencor's enzymatic hydrolysis division, and is the President of the Russian Biofuels Association as well as General Manager of NanoTaiga, a company in Russia using CelloFuel technologies in Russia.

Alan Pryce, CEng is Chief Engineer. Alan is an experienced professional mechanical engineer - Chartered Engineer (CEng) – Member of the Institute of Mechanical Engineers (IMechE) - with 10+ years’ experience in the mechanical design and project management of factory automation projects in UK and European factories. He has been a Senior Design Consultant and project manager for over 30 years working for Frazer-Nash Consultancy Ltd involved with many design and build contracts in the military, rail, manufacturing, and nuclear industries.

Maria Kharina, PhD, is Sr. Microbiology Scientist. Maria has a PhD in Biotechnology and is a researcher with 10+ years of experience. Maria was a Fulbright Scholar in the USA from 2016-2017.

Beverley Nash is Director of Marketing. Beverley has run Nash Marketing for over 30 years and has extensive experience in marketing planning and development for both new and established businesses. Beverley has worked for many global corporations in the technical marketplace and has been responsible for both the planning and management of many programs dealing with all aspects of company and product growth.

Dr. Ryan P. O'Connor (www.oconnor-company.com) provides intellectual property strategy consulting and patent prosecution. Dr. O'Connor holds a degree in Chemical Engineering from University of Notre Dame and a Ph.D. in Chemical Engineering from University of Minnesota. He has filed more than 1000 U.S. and PCT applications and is admitted to the Patent Bar, United States Patent & Trademark Office.

Hamrick Engineering Patent Portfolio