Double T-junction microfluidic and conventional dripping systems for Bacillus subtilis immobilization in calcium alginate microparticles for lipase production

Abstract

Bacillus subtilis immobilization in calcium alginate microparticles was investigated using two techniques: droplet microfluidics-based in T-junction geometry composed with a double droplet generation system and conventional dripping system. Alginate microparticles produced by microfluidic technology presented an average size of 68.35 µm with low polydispersity and immobilization efficiency around 86%. The cell response was evaluated in batch cultivation for 24 h, viewing lipase production compared to free cells. In this study, the batch cultivation with immobilized cells in alginate microparticles presented lipase production about 2.4 and 1.7 times higher than cultivation with cells immobilized cells by conventional technique and free cells cultivations. According to the results, this main novelty of the double T junction technique is an innovative contribution as a tool for cell immobilization on a laboratory scale, since the cultivation of immobilized cells in microparticles of small size and low polydispersity favors cell growth and increases the productivity of important metabolites of industrial biotechnology.

Keywords: Alginate microparticles; Bacillus subtilis; Cell immobilization; Dripping technique; Lipase; Microfluidics; T-junction droplet microfluidic.