Sophorolipids are glycolipids that have natural antimicrobial properties and present great potential in the pharmaceutical field. The present study aimed to produce sophorolipids from Candida bombicola using a chicken fat-based medium and evaluate the antimicrobial activity against Gram-negative (Proteus mirabilis, Escherichia coli, Salmonella enterica subsp. enterica) and Gram-positive bacteria (Enterococcus faecium, Staphylococcus aureus and Streptococcus mutans). The production of sophorolipids reached 27.86 g L-1. Based on the structural characterization, 73.55% of the sophorolipids present a mixture of acidic monoacetylated C18:2 and lactonic diacetylated C16:0, and 26.45% were present in the diacetylated C18:1 lactonic form. Bacteria submitted to sophorolipid exposure showed a reduction in viability at doses of 500 μg mL-1 and 2,000 μg mL-1 against Gram-positive and Gram-negative bacteria, respectively. These results suggest that sophorolipids produced in chicken fat medium may be used as antimicrobial agents to prevent or eliminate contamination by different pathogens.

The aims of this work were to produce hyaluronic acid (HA) by Streptococcus zooepidemicus ATCC 39920 in a low cost sugarcane molasses fermentation medium and to employ the produced HA to obtain films blends based on polyvinyl alcohol (PVA). The films were produced using solution casting method and they were characterized according to their microstructure, mechanical and barrier properties. HA was added in different concentrations (0, 5, 10 and 15% (w/w)), and glycerol was used as a plasticizer (25 g/100 g solids). All formulations resulted in easily manipulated films with good appearance. The addition of HA on PVA films increased their thermal stability, solubility, swelling index, water vapor permeability and elongation. Microbial HA sample combined with PVA showed to be a promising material to biomedical application, and an addition between 5 and 10% (w/w) was sufficient to improve PVA films properties.

Effect of fermentation conditions on the production of hyaluronic acid by Streptococcus zooepidemicus ATCC 39920

Pseudomonas aeruginosa is a metabolically versatile opportunistic pathogen capable of surviving in a range of environments. The major contribution to these abilities relies on virulence factor production, e.g., exotoxins, phenazines, and rhamnolipids, regulated through a hierarchical system of communication, named quorum sensing (QS). QS involves the production, release, and recognition of two classes of diffusible signal molecules: N-acyl-homoserine lactones and alkyl-quinolones. These present a central role during P. aeruginosa infection, regulating bacterial virulence and the modulation of the host immune system. The influence of this arsenal of virulence factors on bacterial–host interaction makes P. aeruginosa a highly potential platform for the development of biopharmaceuticals. Here, we comprehensively reviewed the therapeutical applications of P. aeruginosa virulence factors and quorum sensing signaling molecules on pathological conditions, ranging from infections and inflammation to cancer disease.