L-lysine production improvement: a review of the state of the art and patent landscape focusing on strain development and fermentation technologies.

L-lysine is an essential amino acid used in various industrial sectors but mainly in food and animal feed. Intense research has been directed toward increasing its productivity. This literature review presents the state of the art and patent landscape of the industrial production of L-lysine, with a focus on the strain development and fermentation technologies, through geographic, social, and chronological analysis, using the text mining technique. The geographic analysis showed a greater tendency for countries with industrial plants with large production capacity to submit patents or publish articles, while the social analysis reflected the close relationship between educational units and companies. The technologies of each document were divided into optimization of fermentation parameters, conventional mutation, and genetic engineering. Corynebacterium glutamicum and Escherichia coli present the most attractive industrial phenotypes, and their cultivation occurs mainly in fed-batch processes with control parameters carefully selected to enhance metabolism. These strains are generally modified by conventional approaches (e.g., mutagenesis and selection of auxotrophic and/or regulatory mutants) or by genetic engineering technologies. The combination of both these approaches enables genomic breeding and the construction of strains with industrial potential, capable of accumulating more than 120 g/L of L-lysine. From the analysis of these approaches, we developed a descriptive flow of substrate uptake, amino acid metabolism, and mechanisms of excretion of a lysine-producing model cell. It is expected that the various mechanisms of L-lysine production, here shown and described, will become a guide that aids in increasing amino acid productivity without interfering with the strain stability.

Microbial ecology and starter culture technology in coffee processing.

Coffee has been for decades the most commercialized food product and most widely consumed beverage in the world, with over 600 billion cups served per year. Before coffee cherries can be traded and processed into a final industrial product, they have to undergo postharvest processing on farms, which have a direct impact on the cost and quality of a coffee. Three different methods can be used for transforming the coffee cherries into beans, known as wet, dry, and semi-dry methods. In all these processing methods, a spontaneous fermentation is carried out in order to eliminate any mucilage still stuck to the beans and helps improve beverage flavor by microbial metabolites. The microorganisms responsible for the fermentation (e.g., yeasts and lactic acid bacteria) can play a number of roles, such as degradation of mucilage (pectinolytic activity), inhibition of mycotoxin-producing fungi growth, and production of flavor-active components. The use of starter cultures (mainly yeast strains) has emerged in recent years as a promising alternative to control the fermentation process and to promote quality development of coffee product. However, scarce information is still available about the effects of controlled starter cultures in coffee fermentation performance and bean quality, making it impossible to use this technology in actual field conditions. A broader knowledge about the ecology, biochemistry, and molecular biology could facilitate the understanding and application of starter cultures for coffee fermentation process. This review provides a comprehensive coverage of these issues, while pointing out new directions for exploiting starter cultures in coffee processing.

Added-value biomolecules' production from cocoa pod husks: A review.

Cocoa beans are produced through on-farm processing where residual biomass is discarded, including cocoa pod husks (CPH), cocoa bean shells and cocoa sweatings. CPH represents about 80% of these residues that are generated during the initial cocoa bean processing steps and their disposal occupies large areas, causing social and environmental concerns. In the last decades, the lignocellulosic composition of CPH has attracted the attention of the scientific and productive sector. Recently, some studies have reported the use of CPH in the production of medium to high value-added molecules, with potential applications in food and feed, agriculture, bioenergy, and other segments. This review presents biotechnological approaches and processes for the exploitation of CPH, including pre-treatment methods for the production of different biomolecules. Great perspectives and innovations were found concerning CPH exploitation and valorisation, but still more efforts are needed to valorise this potential feedstock and give support to producers in-development countries.