What is the context of studying the wheat and soil microbiome, and what is the purpose of using microorganisms?
In the face of climate change, the relevance of EU strategies that promote sustainable production is becoming increasingly clear. The concept of “sustainable production” refers to the entire production chain, from agriculture to consumers, and it also includes the use of agricultural by-products and waste.
Microorganisms that naturally occur in soil, plants, and food products play an essential role in this system. Fermentation is one of the oldest food preservation methods and has recently attracted renewed interest, particularly lactic acid fermentation driven by lactic acid bacteria (LAB). A better understanding of the microbiome and the interactions between microorganisms allows their deliberate use at various stages of production.
Microorganisms act as natural cell factories, transforming plant material, altering its properties, and shaping its quality. Harnessing their potential begins with studying the microbiomes of soil and plants. Through the exploration of microbial communities that inhabit ecological niches linked to food and feed production, it is possible to identify and isolate strains that can be developed as starter cultures. Such native microorganisms can enhance food and feed by eliminating harmful compounds and introducing desirable traits. In this context, microbiological preparations can be developed for soils and plants, along with starter cultures containing native environmental bacteria, to process and preserve both primary and waste plant materials through fermentation.
Wheat processing generates by-products such as bran, meal, germ, straw, surplus bread, and spent grain. Many of these materials have long been used in feed and can provide clear benefits when applied strategically, although limitations remain. A key challenge is the presence of antinutritional factors such as phytic acid (IP6), which binds minerals and reduces their bioavailability.
What nutrients do these products contain and how are they altered by fermentation?
Wheat bran is rich in fiber, protein, B vitamins vitamins (especially niacin, thiamine, riboflavin, pyridoxine, and folate), minerals (iron, zinc, magnesium, manganese, selenium, phosphorus, potassium), antioxidants, and phytochemicals such as phenolic acids, alkylresorcinols, lignans, and tocopherols. However, many nutrients are partly bound by fiber and phytic acid. Fermentation can release these nutrients, improving mineral bioavailability, enhancing antioxidant activity, increasing B-vitamin content, and improving digestibility. Bran components such as arabinoxylans and ferulic-acid–rich oligosaccharides also act as prebiotic fibers supporting gut health. Thus, fermentation transforms wheat bran from a simple bulk feed into a nutrient-rich ingredient.
How Fermentation Alters Wheat Bran Nutrients
Fiber modifications due tu microbial partial breakdown of insoluble fiber result in more soluble fiber, improving fermentability and prebiotic properties, release of bound phenolics (e.g., ferulic acid) from cell wall complexes. Hydrolysis of phenolic compounds leasd to more free phenolics with higher antioxidant capacity.
Other beneficial transformations of raw material components by microorganisms include proteolysis of protein what increases free amino acids and short peptides, certain lactic acid bacteria can synthesize B vitamins, improve mineral bioavailability due to phytase activity (accesing, freeing phosphorus, iron, zinc, calcium, magnesium. During fermentation LAB produce organic acids (lactic, acetic) that help preserve the bran and improve flavor.
How were bacteria selected for fermentation of wheat waste?
First of all, only microorganisms with a documented history of use and ‘safe’ status were taken into account (qualified presumed safety (QPS) or GRAS status). Another important issue was the origin of microorganisms (source of isolation) determining their potential adaptation to the plant matrix environment and, on the other hand, their planned use as a feed additive. Plant environments such as wheat grain, wheat flour, wheat sourdough and wheat waste as well as the digestive tract of poultry were considered.
The next stage of selection included the study of properties of microorganisms important for use in feed, such as production of exopolysaccharides (EPS), antagonistic properties against molds and pathogenic bacteria, anti-inflammatory effect, wide carbon sources utilization spectrum, and antioxidant effect.
Technological features such as high efficiency and growth rate in culture, high acidification rate, the wide spectrum of produced enzymes, and arabinoxylan degradation ability are also important.
Finally, taking into account the properties of microorganisms and the characteristics of the biomass of fermented wheat bran obtained from their use, three strains of bacteria were selected for scale-up studies and feeding experiments with chickens. Selected bacterial strains: Lactiplantibacillus plantarum, Pediococcus acidilactici and Weissella cibaria belong to species of QRS status, which are used as probiotic preparations in animal nutrition. Even though the fermented wheat bran is planned to be dried, a small number of lactic acid bacteria may survive in the feed (below 100 cfu/g).
How the bacteria were prepared and the bran fermentation carried out as an ingredient incorporated into the feed
Bacterial strains intended for inoculation of wheat bran fermentation were cultured in bioreaktor and freeze-dried. Preservation of bacterial strains in a freeze-dried form is an element of standardization of the fermentation process and maintaining repeatable process conditions.
Implementation and validation of novel fermented feed products for poultry
The parameters of the wheat bran fermentation process with starter cultures of selected bacterial strains were developed, determined and confirmed on a microtechnical scale. A semi-solid fermentation system was used, which means that the water content during fermentation did not exceed 60%. Final processing included drying, milling and pelleting. The obtained wheat bran – based fermentation products were characterized by good physicochemical parameters, i.e. protein, crude fiber, fat, ash, NFC – required for obtaining good quality feed ingredient. SOP has been developed for the production of a prototype, which will be verified on a semi-technical scale. Scaling up were progressive (1.5L, 30L and 1500L). To produce stable and good quality fermented feed, several batches of 16L fermentation were produced and mixed for studies on poultry.
What are the benefits of adding fermented wheat waste as feed ingredients to farm animal?
- Nutritional
Wheat bran/middlings provide protein, fiber, minerals, and energy, making them common inclusions in ruminant, swine, and poultry diets. Fermented or enzyme-treated wheat by-products can increase digestibility and energy availability, especially in monogastrics.
- Functional
-Fermentation of wheat bran generate lactic acid–enriched feeds, which enhance palatability and animal health. Wheat bran’s arabinoxylans and ferulic-acid–rich fibers act as prebiotics, supporting beneficial gut microbes and modulating immunity. Challenges are Non Fiber limits in monogastrics: High bran inclusion can depress growth performance in poultry and pigs if not balanced with digestible energy/protein.
-Sustainability and Economics. The use of wheat by-products helps reduce waste, lower feed costs, and reduce the environmental impact of both livestock production and wheat processing.
Fermentation of wheat waste increases its usefulness and effectiveness as a feed ingredient. The use of wheat waste in feed and provides an economical component in poultry diets.
Lukasz Wozniak
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