From the Bioreactor to the Field: The Role of Ingredients in Microbial Agrochemical Production

Paolo Bravini

Global Business Development Manager Agrochemicals, IMCD Group

A Shift Toward Sustainable Inputs

As global agriculture faces increasing pressure to reduce environmental impact, the agrochemical industry is undergoing a profound transformation. Chemical pesticides and synthetic fertilizers - once the cornerstones of crop protection and nutrition - are now being reassessed considering their long-term effects on soil health, biodiversity, and food safety. In response, both regulatory bodies and market forces are accelerating the transition toward sustainable alternatives.

Among the most promising solutions are microbial active ingredients and microbial fertilizers, which offer targeted, biodegradable, and often multi-functional effects. These living or metabolite-based products including biopesticides, bio-stimulants, and biofertilizers align with sustainable farming principles and are increasingly adopted in both conventional and organic agriculture.

However, the success of these biologicals depends not only on the strains themselves, but also on the ingredients and technologies that support their development from upstream fermentation to downstream stabilization and formulation. This is where IMCD steps in as a strategic partner, providing a broad portfolio of functional ingredients specifically designed to meet the unique challenges of microbial production. Whether it's nutrients for microbial growth, sterilizable antifoams, cryoprotectants, suspension stabilizers, or UV filters, IMCD delivers technical expertise and supply chain reliability tailored to the needs of the biological agrochemical sector.

The Building Blocks of Microbial Fermentation

At the heart of every successful microbial product lies a finely tuned fermentation process. This complex biological operation requires a balanced selection of ingredients to fuel microbial growth, optimize metabolite production, and maintain process stability.

Carbon Sources: Energy for Microbial Metabolism

Carbon is the primary energy source for microbial cells. While glucose is a commonly used carbohydrate due to its high solubility and fast uptake, other options such as maltodextrins or sugar alcohols offer benefits like osmotic balance and controlled energy release. The choice of carbon source can significantly influence growth kinetics, biomass yield, and final product composition—especially in the production of spores, enzymes, or bioactive compounds.

Nitrogen Sources: Supporting Growth and Productivity

Nitrogen is essential for protein and nucleic acid synthesis. Organic nitrogen sources like yeast extracts and plant-based peptones outperform inorganic options in many fermentation processes. These complex substrates have proven effective in cultivating strains like Bacillus thuringiensis and Bradyrhizobium japonicum, leading to higher biomass yields and enhanced spore viability. Animal-free hydrolysates derived from soy or pea proteins, in particular, offer excellent performance with low endotoxin levels and good filterability.

Growth Enhancers and Functional Nutrients

In addition to basic carbon and nitrogen, certain functional ingredients—such as nucleotide-rich yeast extracts and trace mineral blends—can significantly enhance microbial metabolism. These components support faster fermentation cycles, higher cell densities, and more robust metabolite output. Strategic pairing of these enhancers with optimal carbon sources has been shown to increase viable biomass yields by 300–500% in select microbial fermentations.

Buffering Agents and Trace Elements

Maintaining optimal pH during fermentation is crucial, as microbial metabolism often generates acidic or alkaline byproducts. Buffering agents such as phosphate salts help stabilize the environment, while trace elements like magnesium, manganese, and iron are essential cofactors for enzymatic pathways. Customized supplementation ensures that microbial performance is not limited by hidden nutritional deficiencies.

Foam Control: The Role of Antifoams in Optimized Fermentation

Foaming is a frequent issue in aerobic fermentation, where high agitation and aeration rates are used. Non-silicone antifoams offer a reliable solution, particularly for sensitive strains and sterile processes. These formulations are autoclavable, chemically inert, and do not interfere with oxygen transfer—making them ideal for modern microbial production where process control and product purity are paramount.

Downstream Processing and Stabilization

Once fermentation is complete, microbial biomass must be harvested, stabilized, and formulated into a form suitable for agricultural use. This downstream phase is as critical as fermentation itself, determining product shelf life, usability, and field efficacy.

Biomass Recovery and Separation

Separation techniques such as centrifugation, filtration, and decantation are used to isolate microbial cells or spores from the fermentation broth. This step is crucial for concentrating actives, minimizing contaminants, and preparing for drying or formulation.

Drying Technologies: Preserving Viability and Performance

Two primary drying methods are used in microbial production:

• Freeze drying (lyophilization) is ideal for heat-sensitive strains, preserving structural integrity by sublimating moisture under vacuum at low temperatures.

• Spray drying offers faster processing and cost efficiency, suitable for more robust organisms. Formulation aids are often needed to protect cells from thermal stress.

Protective agents such as sugars, polyols, or proteins are added prior to drying to enhance cell survival. These compounds form a stabilizing matrix around microbial cells, shielding them during dehydration.

Suspension Stabilizers and Cryoprotectants

In liquid or concentrated formulations, maintaining a stable suspension is vital:

• Low-viscosity colloidal microcrystalline cellulose (MCC) is widely used to prevent sedimentation and ensure even distribution of microbial cells.

• Alginates, natural polymers from brown algae, offer encapsulation and rheological benefits, acting as both protective agents and physical stabilizers.

• DMSO (dimethyl sulfoxide) serves as a cryoprotectant in freeze-dried formulations, especially for sensitive strains, by preventing ice crystal damage during freezing.

Coformulants

To ensure effective field application, microbial formulations must maintain physical and functional consistency IMCD offers an extensive portfolio of coformulants. 

Surfactants, especially dispersing and wetting agents, enhance the distribution of microbial cells on plant surfaces and in soil environments. They improve spreading, adhesion, and re-suspension—key for foliar sprays and tank mixes.

Rheology modifiers help control viscosity and flow behavior, preventing sedimentation in storage and reducing equipment clogging. Together, these formulation aids ensure product stability, ease of application, and uniform field performance.

UV Protection for Foliar Applications

Microbial actives applied to foliage are often vulnerable to UV degradation, especially in open-field conditions. To combat this, colloidal lignin-based UV filters are used as natural protective agents. These materials absorb harmful UV radiation while being biodegradable and plant-compatible. When integrated into suspensions or coatings, colloidal lignin helps preserve microbial viability on the leaf surface, extending the window of action and improving product consistency across variable climates.

Microbial Inputs at the Core of Sustainable Agriculture

The shift toward microbial crop inputs is not merely a trend—it’s a strategic realignment toward more resilient, ecologically responsible farming systems. Microbial products bring inherent advantages: natural modes of action, reduced risk of resistance, and compatibility with soil health and biodiversity goals. They are central to achieving global sustainability targets, from carbon footprint reduction to regenerative agriculture.

Still, the success of microbial products depends on more than just the strains themselves. The entire ecosystem of fermentation nutrients, processing aids, and formulation ingredients determines whether a microbial concept becomes a viable, scalable solution. This is where IMCD adds tangible value—as a reliable, innovation-driven partner offering not only a full spectrum of high-quality ingredients, but also the technical support to help optimize process performance and product stability at every stage.

With a footprint across all major agricultural markets and deep application know-how, IMCD supports microbial producers in scaling innovation—efficiently, sustainably, and competitively. Whether you're developing next-generation inoculants, biocontrol agents, or biostimulants, IMCD provides the ingredients, insights, and infrastructure to bring biological products from the bioreactor to the field.

About IMCD

IMCD is a leading global distributor and formulator of specialty chemicals and ingredients, offering a wide portfolio of inerts, seed coatings, polymers, and biostimulants. Our solutions enhance formulation performance, stability, and delivery efficiency, enabling safer, more sustainable agrochemical products. By replacing non-biodegradable or hazardous inerts, we help formulators develop high-performance, eco-friendly solutions for plant nutrition and crop protection.

Collaborate with IMCD to drive innovation and sustainability in agrochemical formulations.

Find out more: https://www.imcdgroup.com/ 

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This article will be published in the magazine of 2025 Biologicals Special. Follow this magazine to read more articles/stories.