Microencapsulation extends mycelial viability of Streptomyces lividans 66 and increases enzyme production

Filamentous bacteria of the genus Streptomyces produce a large arsenal of industrially relevant antibiotics and enzymes. The industrial production of these molecules occurs in large fermenters, where many streptomycetes form dense mycelial networks called pellets. Pellets are characterized by slow growth and inefficient nutrient transfer and therefore regarded as undesirable from the perspective of productivity. Although non-pelleting strains have increased growth rates, their morphology also leads to a dramatic increase in the viscosity of the culture broth, which negatively impacts the process dynamics.

Here, we applied immobilization of Streptomyces lividans 66 using alginate as semi-solid matrix. This alginate-mediated micro-encapsulation increased the production of the extracellular enzyme tyrosinase more than three-fold. The increased production was accompanied by extended viability of the mycelium and a dramatic reduction in the release of intracellular proteins into the culture broth.

Our data demonstrate the utility of micro-encapsulation as a powerful technique to achieve higher yields and lower downstream-processing costs of streptomycetes.