ABSTRACT
Abstract The human gastrointestinal (GI) tract is colonized by a complex and dense microbial community that can be divided into three major phyla-Bacteroidetes, Firmicutes and Actinobacteria, which, under normal conditions, live in a symbiotic relationship with the host. However, it has been shown that a dysfunctional interaction between the microbiota and the host can lead to several intestinal disorders, thus being considered a field of growing interest by the scientific community. In this context, some studies have been carried out to elucidate functions of true resident bacteria, while other research has attempted to assess transient bacteria. In addition, some studies have focused on the group of lactic acid bacteria (LAB) that are widely used as starter cultures in food fermentation of a large variety of fermented foods. It has being reported that allochthonous LAB bacteria may have positive effects on the host when administrated in adequate amounts, thereby allowing them to be classified as probiotics microorganisms. Our research group recently investigated the mechanisms underlying the protective effects of dairy Lactobacillus delbrueckii Lb CNRZ327 in vitro and in vivo assays and have deposited the complete genome of Lactococcus lactis NCDO 2118, which will enable a greater understanding of its intrinsic characteristics. Beyond the classical employment of LAB, our group gathered research works using genetically engineered LABs, more specifically lactococci and lactobacilli as mucosal delivery vectors for therapeutic proteins and DNA
Fermented Foods of Latin America
vaccines. In this context, several studies have been conducted to develop new strains and efficient expression systems to use LAB as “cell factories” for the production of anti-inflammatory proteins, where we provide the recombinant Lactococcus lactis strains efficiency in the prevention of the intestinal damage associated with inflammatory bowel disease in murine models. Moreover, the use of LAB as cell carriers for the production and presentation of antigens has contributed significantly to the development of new vaccines. A growing number of publications on biotechnological or therapeutic employment of LAB has emerged showing their effectiveness against disease but also its safety and immune efficiency, the fact that there are varied ongoing studies with tests at different stages of clinical phase, strengthens our belief that their use will soon benefit the population against most diseases whose treatment and cure is difficult or non-existent.
