Bread as a Valuable Raw Material in Craft Ale Beer Brewing.

One of the ingredients used for brewing is barley, which should be malted; it is considered the most polluting agricultural input. On the other hand, food wastage is today a widespread problem that causes significant environmental damage and also generates large economic losses worldwide. One of the most wasted food products is bread; it is estimated that hundreds of tons of bread are wasted every day worldwide. In this study, the brewing of ale beers with bread was carried out. For this purpose, up to 50% of the malt weight was replaced by different types of bread: wheat bread, whole wheat bread, rye bread, and corn bread. A physicochemical and sensory comparison was made with 100% malt ale beer. All beers brewed with bread had an alcoholic strength similar to that of the control beer, except the corn beer. Beers brewed with whole grain bread showed a higher antioxidant capacity and a higher total polyphenol content. The sensory analysis presented different profiles depending on the type of bread; in general, the addition of bread created a greater olfactory intensity in nose. Thus, it was found that it is possible to brew beer with bread substituting up to 50% of the malt. In addition, it was also shown that the beer brewed with whole wheat bread had similar characteristics to the control beer, even improving some beneficial health properties, representing a great advantage for the brewing industry all over the world.

Utilization of xylose by engineered strains of Ashbya gossypii for the production of microbial oils.

BACKGROUND: Ashbya gossypii is a filamentous fungus that is currently exploited for the industrial production of riboflavin. The utilization of A. gossypii as a microbial biocatalyst is further supported by its ability to grow in low-cost feedstocks, inexpensive downstream processing and the availability of an ease to use molecular toolbox for genetic and genomic modifications. Consequently, A. gossypii has been also introduced as an ideal biotechnological chassis for the production of inosine, folic acid, and microbial oils. However, A. gossypii cannot use xylose, the most common pentose in hydrolysates of plant biomass. RESULTS: In this work, we aimed at designing A. gossypii strains able to utilize xylose as the carbon source for the production of biolipids. An endogenous xylose utilization pathway was identified and overexpressed, resulting in an A. gossypii xylose-metabolizing strain showing prominent conversion rates of xylose to xylitol (up to 97% after 48 h). In addition, metabolic flux channeling from xylulose-5-phosphate to acetyl-CoA, using aheterologous phosphoketolase pathway, increased the lipid content in the xylose-metabolizing strain a 54% over the parental strain growing in glucose-based media. This increase raised to 69% when lipid accumulation was further boosted by blocking the beta-oxidation pathway. CONCLUSIONS: Ashbya gossypii has been engineered for the utilization of xylose. We present here a proof-of-concept study for the production of microbial oils from xylose in A. gossypii, thus introducing a novel biocatalyst with very promising properties in developing consolidated bioprocessing to produce fine chemicals and biofuels from xylose-rich hydrolysates of plant biomass.

Engineering Ashbya gossypii strains for de novo lipid production using industrial by-products.

Ashbya gossypii is a filamentous fungus that naturally overproduces riboflavin, and it is currently exploited for the industrial production of this vitamin. The utilization of A. gossypii for biotechnological applications presents important advantages such as the utilization of low-cost culture media, inexpensive downstream processing and a wide range of molecular tools for genetic manipulation, thus making A. gossypii a valuable biotechnological chassis for metabolic engineering. A. gossypii has been shown to accumulate high levels of lipids in oil-based culture media; however, the lipid biosynthesis capacity is rather limited when grown in sugar-based culture media. In this study, by altering the fatty acyl-CoA pool and manipulating the regulation of the main ∆9 desaturase gene, we have obtained A. gossypii strains with significantly increased (up to fourfold) de novo lipid biosynthesis using glucose as the only carbon source in the fermentation broth. Moreover, these strains were efficient biocatalysts for the conversion of carbohydrates from sugarcane molasses to biolipids, able to accumulate lipids up to 25% of its cell dry weight. Our results represent a proof of principle showing the promising potential of A. gossypii as a competitive microorganism for industrial biolipid production using cost-effective feed stocks.

Bioproduction of riboflavin: a bright yellow history.

Riboflavin (vitamin B2) is an essential nutrient for humans and animals that must be obtained from the diet. To ensure an optimal supply, riboflavin is used on a large scale as additive in the food and feed industries. Here, we describe a historical overview of the industrial process of riboflavin production starting from its discovery and the need to produce the vitamin in bulk at prices that would allow for their use in human and animal nutrition. Riboflavin was produced industrially by chemical synthesis for many decades. At present, the development of economical and eco-efficient fermentation processes, which are mainly based on Bacillus subtilis and Ashbya gossypii strains, has replaced the synthetic process at industrial scale. A detailed account is given of the development of the riboflavin overproducer strains as well as future prospects for its improvement.

Engineering Ashbya gossypii for efficient biolipid production.

Ashbya gossypii is a filamentous fungus that naturally overproduces riboflavin. Indeed, engineered strains are currently used for the industrial production of riboflavin, replacing the chemical synthesis processes formerly used. The utilization of A. gossypii for biotechnological applications affords significant advantages that involve low-cost media use and cheap downstream processing for some applications. Although A. gossypii cannot be considered a bona fide oleaginous microorganism, the accumulation of lipid droplets within hyphae has been described. In view of the genomic and molecular tools available for its manipulation, the metabolism of A. gossypii was engineered aiming to increase total lipid accumulation. Blocking the ß-oxidation pathway through the knock-out of the AgPOX1 gene was sufficient to obtain strains with high lipid yields, comparable to those of the best oleaginous microorganisms. Thus, the poxΔ strain of A. gossypii constitutes a novel promising tool for the production of microbial oils in forthcoming modified A. gossypii strains.