This study aimed to evaluate technological (acidification, proteolysis, lipolysis, resistance to low pH, NaCl, and bile salts) and biopreservation (antimicrobial activity against foodborne pathogens) features of 1002 LAB by high throughput screening (HTS) methods. The LAB was isolated from 11 types of Brazilian artisanal cheeses (BAC) marketed in the main 5 producing regions. Remarkable intra-species variability in acidification rates have been found, which was most pronounced between isolates from Mina's artisanal cheeses, Caipira and Coalho cheeses. Lacticaseibacillus paracasei and Levilactobacillus brevis showed the fastest acidification rate; however, all isolates showed slower acidification rates than a lactococcal control strain (4.3 × lower). When testing inhibitory effects, > 75% of LAB isolates could inhibit the growth of Staphylococcus aureus ATCC 19095 and Listeria monocytogenes ATCC 7644. Two of these isolates, identified as Lactiplantibacillus plantarum and Lentilactobacillus buchneri, the sterile and neutral supernatants alone, were sufficient to inhibit L. monocytogenes growth. Principal component analysis (PCA) allowed the identification of functional groups based on proteolytic and lipolytic activity, osmotic stress resistance, and inhibition of L. monocytogenes. The type of cheese the isolates were recovered from influenced properties such as anti-listerial compounds and lipolytic enzyme production. The use of HTS and multivariate statistics allowed insights into a diverse set of LAB technological and biopreservation properties. These findings allow a profound knowledge of the heterogeneity of a large set of isolates, which can be further used to design starter cultures with varied and combined properties, such as biopreservation and technological features. Besides that, HTS makes it possible to analyze a vast panel of LAB strains, reducing costs and time within laboratory analysis, while avoiding the loss of information once all LAB are tested at the same time (differently from the traditional labor-intensive approach, in which a few numbers of strains is tested per time).
DOCUMENT
Inoculation of maize silage with Lactobacillus buchneri (5 × 105 c.f.u. g-1 of maize silage) prior to ensiling results in the formation of aerobically stable silage. After 9 months, lactic acid bacterium counts are approximately 1010 c.f.u. g-1 in these treated silages. An important subpopulation (5.9 × 107 c.f.u. g-1) is able to degrade 1,2-propanediol, a fermentation product of L. buchneri, under anoxic conditions to 1-propanol and propionic acid. From this group of 1,2-propanediol-fermenting, facultatively anaerobic, heterofermentative lactobacilli, two rod-shaped isolates were purified and characterized. Comparative 16S rDNA sequence analysis revealed that the newly isolated bacteria have identical 16S rDNA sequences and belong phylogenetically to the L. buchneri group. DNA-DNA hybridizations, whole-cell protein fingerprinting and examination of phenotypic properties indicated that these two isolates represent a novel species, for which the name Lactobacillus diolivorans sp. nov. is proposed. The type strain is LMG 19667T ( = DSM 14421T).
DOCUMENT
Unwanted tomatoes represent ~20% of the European market, meaning that ~3 million metric tons of tomatoes are wasted every year. On a national scale, this translates to 7000 tons of tomato waste every year. Considering the challenge that food spillage represents worldwide and that the Netherlands wants to be circular by 2050, it is important to find a way to circularize these tomatoes back into the food chain. Moreover, tomatoes are the largest greenhouse crop in the Netherlands, which means that reducing the waste of this crop will positively and significantly affect the circularity and sustainability of the Dutch food system. A way to bring these tomatoes back into the food chain is through fermentation with lactic acid bacteria (LAB), which are already used in many food applications. In this project, we will assemble a unique new mix (co-culture) of LAB bacteria, which will lead to a stable fermented product with low sugar, low pH and a fresh taste, without compromising its nutritional value. This fermentation will prevent the contamination of the product with other microorganisms, providing the product with a prolonged shelf life, and will have a positive impact on the health of the consumers. Up until now, only non-fermented products have been produced from rejected tomatoes. This solution allows for an in-between product that can be used towards many different applications. This process will be upscaled to pilot scale with our consortium partners HAN BioCentre, Keep Food Simple, LLTB and Kramer B.V. The aim is to optimize the process and taste the end result of the different fermentations, so the end product is an attractive, circular, and tasty fermented tomato paste. These results will help to advance the circularity and sustainability of our food system, both at a national and European level.
