Hey readers!

Last week the edition went to new molecules and compounds. This week we are back to the microorganisms themselves, still showing how much they can do for crops.

The pieces are a bit longer than usual but totally worth the time 😀!

Here is what is in this one:

Embrapa Meio Ambiente has announced an industrial process for producing fungal bioinsecticides, developed in partnership with the company Efense.

Commercial mycoinsecticides based on Beauveria and Cordyceps commonly rely on aerial conidia produced on solid substrates such as parboiled rice, a process that can take around 10 to 14 days.

Embrapa researchers explored a different route: producing blastospores of Beauveria bassiana BRM 14527 and Cordyceps javanica BRM 14526 through submerged liquid fermentation. Both isolates came from mummified moth cadavers collected in rice crops in Arari, Maranhão.

Blastospores are yeast-like fungal cells that can be produced quickly and at high concentrations in liquid bioreactors. In this study, both fungi exceeded 1 × 10⁹ blastospores per mL within 48 hours of submerged fermentation.

Production was scaled from shake flasks to 7 L bioreactors to 1,200 L stirred tanks, reaching around 1.83 × 10⁹ CFU/mL for B. bassiana and 2.77 × 10⁹ CFU/mL for C. javanica.

Scale was only one part of the problem. Blastospores are more sensitive to drying, UV radiation and other environmental stresses than aerial conidia, which makes shelf life a major limiting factor, and drying them conventionally would require a spray dryer, a freeze dryer or a fluid bed dryer.

The researchers avoided all three, formulating the cells fresh from the broth in oil dispersions and in formulations containing amorphous silica. After 90 days of storage, the best oil-plus-silica formulation held 3.49 × 10⁸ CFU/g for B. bassiana and 2.41 × 10⁷ CFU/g for C. javanica, greater than any other treatment, though the liquid oil dispersion was the more virulent of the two.

The blastospores were highly active against two pests. On their own, at the highest concentration tested, B. bassiana killed 100% of Spodoptera frugiperda (fall armyworm) larvae and C. javanica 87%, while oil-formulated blastospores killed around 85% and 93% of Bemisia tabaci (whitefly) nymphs respectively.

In the field, blastospores produced in the 1,200 L reactors were applied in soybean over two growing seasons and compared with commercial mycoinsecticides based on aerial conidia. The treatments consistently reduced whitefly populations relative to untreated plots, and in several cases performed similarly to or better than the commercial standards. Shelf life, however, was assessed only at 4 °C, and the authors state that their formulations therefore require a cold chain.

The commercial opportunity goes beyond the speed of fermentation. Blastospores can go directly from the bioreactor into formulation without a convective drying step, potentially simplifying production and reducing manufacturing costs. The authors see this as a route toward a new generation of mycoinsecticides.

One of the main reasons microbial inoculants perform inconsistently in natural soils is that the introduced microorganism may struggle to establish in an already competitive microbial community.

Researchers at the University of Copenhagen tested whether a pre-activated inoculum of the phosphorus-solubilizing fungus Penicillium aculeatum ATCC 10409 could establish in a natural agricultural soil and, once established, benefit maize. They incubated the fungus for one week in soil amended with cellulose as a carbon source, together with different phosphorus sources, and only after that activation period was the inoculum mixed into agricultural soil and maize sown. The soil came from a long-term nutrient depletion trial at the University of Copenhagen that has been depleted of phosphorus for 27 years, and it was never sterilised.

The fungus established. The researchers introduced around 2 × 10⁵ conidia per gram of soil, and at harvest 42 days later they recovered between 1.9 × 10⁶ and 4.4 × 10⁶ per gram, so it had also multiplied.

That establishment was accompanied by better maize performance. Inoculated plants were taller from 29 days after sowing onward and produced significantly more shoot and total biomass, while root biomass was unaffected. Every macronutrient measured in the shoot was higher, though nutrient content in the roots was not.

The benefit occurred regardless of the phosphorus source used, which the authors read as a sign that phosphorus solubilization alone does not explain the response.

Once established, P. aculeatum was also associated with changes in the native root fungi. Arbuscular mycorrhizal colonization approximately doubled, while infection by Microdochium bolleyi decreased significantly. The authors report this as the first indication that a Penicillium species may have biocontrol potential against M. bolleyi.

The experiment ran in pots in a growth chamber over 42 days, so field performance remains to be tested. What it does show is that a pre-activated inoculum can establish strongly in natural, non-sterile soil and influence both plant performance and the native root fungi.

Finding a promising microorganism has traditionally meant searching nature for strains that already carry useful traits. A Brazilian startup is betting that developers can go one step further.

Terra Genomics has raised R$18 million, around US$3.3 million, to build a platform for engineering microorganisms used in agricultural biologicals. Founded in 2025, the company combines metabolic engineering, synthetic biology and AI to improve traits such as nitrogen fixation, phosphorus solubilisation, production of bioactive molecules and biological control.

The idea is not to replace microbial discovery, but to add another step after promising strains are identified. Terra Genomics is building a Design-Build-Test-Learn platform where strains can be designed, tested and redesigned based on performance.

The development path, in this model, would be:

isolate → screen → select → engineer → develop

The company plans to offer this capability to biological-input manufacturers that do not have microbial engineering teams in house.

Terra Genomics is still early, and the announcement does not yet include a commercial engineered strain or field-performance data. What it puts on the table is that the next gains in microbial biologicals may come after the strain is found.

Microorganisms can do extraordinary things in the lab. The problem is keeping them functional once they face UV exposure and fluctuating pH and temperature in the real world.

A recent review in Trends in Biotechnology, from Italy's National Research Council in Bologna and the University of Parma, argues that finding a promising strain is only part of the challenge. The next step is designing the material environment that helps it keep working after application.

Encapsulation is therefore moving from passive protection toward actively engineering the microenvironment around the cell. The review describes the goal as a functional microreactor, where alginate, chitosan, silica or calcium-based minerals regulate hydration, diffusion, pH, adhesion, protection and release.

In one tomato study the review cites, an alginate-encapsulated four-strain biocontrol consortium reduced Verticillium dahliae disease severity by 60% and plant mortality by 95% after nine weeks, while the non-encapsulated microorganisms provided only partial control. In another, encapsulating endophytic bacteria in a protective hydrogel kept them active at pH 5.5, where free cells lose viability fast, and field trials reported around 30% higher Brassica napus yields than the non-encapsulated formulation.

There is a trade off. A denser capsule can improve stability and protection, but it can also restrict the movement of nutrients and metabolites that the microorganism needs to function. Softer materials favor microbial activity and exchange with the environment but offer less long-term protection. The challenge is therefore not to maximize protection, but to design the right balance for each application.

Commercially, viability alone is not enough. The authors argue that encapsulation only makes sense when the gains in persistence, delivery or activity justify the extra materials and processing costs.

Formulation, in this view, stops being packaging around the microorganism and becomes part of how microbial performance is designed for the field.