Plant-derived protein hydrolysates (PHs) have gained prominence as plant biostimulants because of their potential to increase the germination, productivity and quality of a wide range of horticultural and agronomic crops. Application of PHs can also alleviate the negative effects of abiotic plant stress due to salinity, drought and heavy metals. Recent studies aimed at uncovering the mechanisms regulating these beneficial effects indicate that PHs could be directly affecting plants by stimulating carbon and nitrogen metabolism, and interfering with hormonal activity. Indirect effects could also play a role as PHs could enhance nutrient availability in plant growth substrates, and increase nutrient uptake and nutrient-use efficiency in plants. Moreover, the beneficial effects of PHs also could be due to the stimulation of plant microbiomes. Plants are colonized by an abundant and diverse assortment of microbial taxa that can help plants acquire nutrients and water and withstand biotic and abiotic stress. The substrates provided by PHs, such as amino acids, could provide an ideal food source for these plant-associated microbes. Indeed, recent studies have provided evidence that plant microbiomes are modified by the application of PHs, supporting the hypothesis that PHs might be acting, at least in part, via changes in the composition and activity of these microbial communities. Application of PHs has great potential to meet the twin challenges of a feeding a growing population while minimizing agriculture’s impact on human health and the environment. However, to fully realize the potential of PHs, further studies are required to shed light on the mechanisms conferring the beneficial effects of these products, as well as identify product formulations and application methods that optimize benefits under a range of agro-ecological conditions.

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Fermented foods have long been produced according to knowledge passed down from generation to generation and with no understanding of the potential role of the microorganism(s) involved in the process. However, the scientific and technological revolution in Western countries made fermentation turn from a household to a controlled process suitable for industrial scale production systems intended for the mass marketplace. The aim of this paper is to provide an up-to-date review of the latest studies which investigated the health-promoting components forming upon fermentation of the main food matrices, in order to contribute to understanding their important role in healthy diets and relevance in national dietary recommendations worldwide. Formation of antioxidant, bioactive, anti-hypertensive, anti-diabetic, and FODMAP-reducing components in fermented foods are mainly presented and discussed. Fermentation was found to increase antioxidant activity of milks, cereals, fruit and vegetables, meat and fish. Anti-hypertensive peptides are detected in fermented milk and cereals. Changes in vitamin content are mainly observed in fermented milk and fruits. Fermented milk and fruit juice were found to have probiotic activity. Other effects such as anti-diabetic properties, FODMAP reduction, and changes in fatty acid profile are peculiar of specific food categories.

The nucleotide sequence of the 4,377-bp chromosomal region of Pseudomonas fluorescens ST that codes for the oxidation of styrene to phenylacetic acid was determined. Four open reading frames, named styA, styB, styC, and styD, were identified in this region. Sequence analysis and biotransformation assays, performed with batch and continuous cultures, allowed us to identify the functions of the sequenced genes. styA and styB encode a styrene monooxygenase responsible for the transformation of styrene to epoxystyrene; styC codes for the second enzyme of the pathway, an epoxystyrene isomerase that converts epoxystyrene to phenylacetaldehyde; and the styD gene produces a phenylacetaldehyde dehydrogenase that oxidizes phenylacetaldehyde to phenylacetic acid. StyA, 415-amino-acids long, was found to be weakly homologous to p-hydroxybenzoate hydroxylase from both P. fluorescens and P. aeruginosa and to salicylate hydroxylase from P. putida, suggesting that it might be a flavin adenine dinucleotide-binding monooxygenase. StyB was found to be partially homologous to the carboxyterminal part of the 2,4-dichlorophenol-6-monooxygenase encoded by plasmid pJP4, while the styC product did not share significant homology with any known proteins. The fourth open reading frame, styD, could encode a protein of 502 amino acids and was strongly homologous to several eukaryotic and prokaryotic aldehyde dehydrogenases. The order of the genes corresponds to that of the catabolic steps. The previously suggested presence of the gene for epoxystyrene reductase, which directly converts epoxystyrene to 2-phenylethanol (A. M. Appl. Environ. Microbiol. 61:121-127, 1996), has not been confirmed by sequencing and by biotransformation assays performed in continuous cultures. A copy of the insertion sequence IS1162, belonging to the IS21-like family of elements, was identified immediately downstream of the styrene catabolic genes.

Background: Vanillin is one of the most important aromatic flavour compounds used in the food and cosmetic industries. Natural vanillin is extracted from vanilla beans and is relatively expensive. Moreover, the consumer demand for natural vanillin highly exceeds the amount of vanillin extracted by plant sources. This has led to the investigation of other routes to obtain this flavour such as the biotechnological production from ferulic acid. Studies concerning the use of engineered recombinant Escherichia coli cells as biocatalysts for vanillin production are described in the literature, but yield optimization and biotransformation conditions have not been investigated in details.

The gluten-free market currently offers a range of products which can be safely consumed by patients affected by celiac disease. Nevertheless, challenges for optimal formulation remain on the way in terms of appreciable texture, flavor, and adequate nutritional characteristics. Within that framework, legumes have recently attracted attention among scientists as structure-and texture-forming agents, as source of nutrients and bioactive compounds, and as a low-glycemic-index ingredient. This work aims at providing an updated and comprehensive overview of the advantages and disadvantages in the use of legumes in gluten-free breadmaking. It also shows how legumes can contribute to tackling the main technological, nutritional, and organoleptic challenges. From this critical analysis, it emerged that viscoelastic properties of gluten-free bread batter can be enhanced by the use of carob germ, chickpea, lupin, and soybean. Gluten-free bread organoleptic acceptability can be improved by incorporating leguminous flours, such as carob, chickpea, lupin, and soybean. Moreover, a better nutritional quality of gluten-free bread can be obtained by the addition of chickpea and soybean. Gaps and needs in the use of legumes in gluten-free breadmaking emerged and were gathered together to have a sound basis for future studies. The technological and nutritional potential of sourdough should be more extensively exploited. Moreover, in vitro and in vivo studies should be prompted to understand the health benefits of bread formulated with legumes. A holistic approach, interfacing food science, nutrition, and health might help to have, on the market, products with improved sensory properties and nutritional profile.

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From a ferulic-acid-degrading Pseudomonas fluorescens strain (BF13), we have isolated a transposon mutant, which retained the ability to bioconvert ferulic acid into vanillic acid but lost the ability to further degrade the latter acid. The mutant, BF13-97, was very stable, and therefore it was suitable to be used as a biocatalyst for the preparative synthesis of vanillic acid from ferulic acid. By use of resting cells we determined the effect on the bioconversion rate of several parameters, such as the addition of nutritional factors, the concentration of the biomass, and the carbon source on which the biomass was grown. The optimal yield of vanillic acid was obtained with cells pregrown on M9 medium containing p-coumaric acid ( Lignin-related aromatic acids, which contain phenylpropane (C 6 -C 3 ) type structures (such as ferulic acid and related compounds), are abundant molecules that play important functions in plant cells, as antimicrobial compounds, signaling molecules, and phytoalexins (23). They commonly occur, free or in combined form, in fruits, vegetables, grains, beans, leaves, seeds, nuts, grasses, flowers, and other types of vegetation and can be easily extracted from some agriculture by-products (22). The catabolism of these compounds is an important aspect for the mineralization of plant wastes because they are released during the breakdown of lignin and cell wall materials by white-rot fungii. Moreover, there is a growing interest in the potential use of ferulic acid as feedstock for the biocatalytic conversion into other valuable molecules such as styrenes, polymers, epoxydes, alkylbenzenes, vanillin and vanillic acid derivatives, guaiacol, cathecol, and protocatechuic-acid-related cathecols (22).We previously isolated a Pseudomonas fluorescens strain, named BF13, which utilized some phenylpropenoids (ferulic and m-and p-coumaric acids) as the sole carbon source (4). This strain, when degrading ferulic acid, transiently forms in the culture medium a certain amount of vanillic acid. The latter is a valuable product, used as a starting material in the chemical synthesis of oxygenated aromatic chemicals, such as vanillin, one of the most important flavor molecules (7,22). We studied the possibility of enhancing the formation of vanillic acid during ferulic acid degradation by using suspensions of BF13 cells at high density. We demonstrated that the use of cells not adapted to ferulic acid improved the production of vanillic acid, which remained in the medium for a long period, facilitating its recovery (4). Moreover, we observed that this strain tolerated, better than others, high concentrations of ferulic acid and vanillic acid, which is a relevant property in view of a bioconversion process (unpublished data).In this work our aim was to isolate a mutant of P. fluorescens BF13 which was unable to bioconvert vanillic acid into protocatechuic acid and use this mutant as a biocatalyst for the production of vanillic acid. The molecular characterization of this mutant allowed us to clone the genes fro...