The production of fuels and other industrial products from renewable sources has intensified the search for new substrates or for the expansion of the use of substrates already in use, as well as the search for microorganisms with different metabolic capacities. In the present work, we isolated and tested a yeast from the soil of sugarcane irrigated with vinasse, that is, with high mineral content and acidic pH. The strain of Meyerozyma caribbica URM 8365 was able to ferment glucose, but the use of xylose occurred when some oxygenation was provided. However, some fermentation of xylose to ethanol in oxygen limitation also occurs if glucose was present. This strain was able to produce ethanol from molasses substrate with 76% efficiency, showing its tolerance to possible inhibitors. High ethanol production efficiencies were also observed in acidic hydrolysates of each bagasse, sorghum, and cactus pear biomass. Mixtures of these substrates were tested and the best composition was found for the use of excess plant biomass in supplementation of primary substrates. It was also possible to verify the production of xylitol from xylose when the acetic acid concentration is reduced. Finally, the proposed metabolic model allowed calculating how much of the xylose carbon can be directed to the production of ethanol and/or xylitol in the presence of glucose. With this, it is possible to design an industrial plant that combines the production of ethanol and/or xylitol using combinations of primary substrates with hydrolysates of their biomass.

Food waste (FW) is a common source of contamination, contaminating both soils and water bodies by releasing greenhouse gases. FW holds great potential for biofuel and bioproduct production, which can mitigate its environmental impact and become a valuable addition to the circular bioeconomy. Therefore, this work aimed to investigate the use of food waste as a substrate to produce fermentable sugars and bioethanol. FW was pretreated by lipid removal. Raw and treated FW was hydrolyzed by amylases. Also, FW was hydrolyzed using sulfuric acid under different residence times (20, 40, and 60 min), sulfuric acid concentrations (0.5, 1.0, and 1.5% v·v⁻¹), solid loads (5, 10, and 15% m·v⁻¹), and temperatures (111, 120, and 127 °C). The best reducing sugar concentration was obtained at a 1.5% concentration of sulfuric acid and a 15% solid load applied for 1 h at 127 °C. The acid hydrolysis process was more efficient (76.26% efficiency) than the enzymatic one (72.7%). Bioethanol production was carried out as static submerged fermentation, with Saccharomyces cerevisiae at 10% (humidity m·v⁻¹) being used as the producer and the acid and enzymatic hydrolysates being used as carbon sources. Lipid removal from FW did not influence the acid or enzymatic hydrolytic processes. For fermentation, the highest bioethanol yield was obtained from the acid hydrolysate of raw FW (0.49 kg·kg glicose⁻¹). Thus, the processes used were efficient for bioethanol production, presenting alternatives for sustainable food waste destinations and low-cost biofuel production.

Food waste (FW) presents a critical issue, representing an environmental liability and a largely untapped resource. Its heterogeneity and low valorization rate among main-stream alternative treatments challenge its integration into economically and environmentally sustainable bioprocesses. We explore biorefineries as a solution that can address the complexity of urban food waste through biological strategies capable of converting food waste into valuable products. Exploring the current landscape of FW biorefineries, this study focused on the interplay between feedstock heterogeneity, pretreatment strategies, microbial dynamics, and integration potential. We propose a framework distinguishing between robust fermentations that can use minimally treated FW and tailored fermentations, which require refined media pretreatment and/or supplementation to yield higher-value compounds. Drawing on recent techno-economic and life cycle assessments, this article evaluates process viability and environmental impacts across multiple scales, reinforcing the need for robust analysis to support decision-making. Real-world initiatives and policy frameworks are analyzed to contextualize technological advances within regulatory and infrastructural realities. By linking practical constraints to biochemical and operational strategies, this work outlines how food waste biorefineries can contribute meaningfully to circular economy goals. Instead of treating FW as an intractable problem, it is seen as a versatile feedstock that demands integration, investment, and adaptive process design.

The production of fuels and other industrial products from renewable sources has intensified the search for new substrates or for the expansion of the use of substrates already in use, as well as the search for microorganisms with different metabolic capacities. In the present work, we isolated and tested a yeast from the soil of sugarcane irrigated with vinasse, that is, with high mineral content and acidic pH. The strain of Meyerozyma caribbica URM 8365 was able to ferment glucose, but the use of xylose occurred when some oxygenation was provided. However, some fermentation of xylose to ethanol in oxygen limitation also occurs if glucose is present. This strain was able to produce ethanol from molasses substrate with 76% efficiency, showing its tolerance to possible inhibitors. High ethanol production efficiencies were also observed in acidic hydrolysates of each bagasse, sorghum, and cactus pear biomass. Mixtures of these substrates were tested and the best composition was found for the use of excess plant biomass in supplementation of primary substrates. It was also possible to verify the production of xylitol from xylose when the acetic acid concentration is reduced. Finally, the proposed metabolic model allowed calculating how much of the xylose carbon can be directed to the production of ethanol and/or xylitol in the presence of glucose. With this, it is possible to design an industrial plant that combines the production of ethanol and/or xylitol using combinations of primary substrates with hydrolysates of their biomass.

This study aims to evaluate the use of sugarcane industry byproducts (bagasse and molasses), as well as glycerol from the liquor of the organosolv pretreatment of bagasse, to bioproduce 1,3-propanediol (1,3-PDO). For this purpose, Lentilactobacillus diolivorans was used, which can produce 1,3-PDO from a mixture of glycerol and sugars. First, experiments were conducted using the MRS medium to investigate the effect of various carbohydrate sources and their mixtures on the growth profile and 1,3-PDO production by L. diolivorans. Subsequently, the carbohydrates in the MRS medium were replaced with sugarcane byproducts. The results showed that the type of carbohydrate plays a crucial role in growth kinetics and 1,3-PDO production. Xylose and glucose showed the best results; however, sucrose was not enough to support biomass formation. The presence of xylose increased sucrose assimilation, resulting in a 4.5-fold increase in the concentration of 1,3-PDO from 1.3 to 6.18 g/L. An auspicious outcome was observed when the liquor of the acid pretreatment of sugarcane bagasse, molasses, and organosolv liquor were used as substrates, resulting in a production of 5.47 g/L 1,3-PDO with an efficiency of 82.77%. Therefore, producing a high-value chemical such as 1,3-PDO from the sugarcane byproducts seems to be a very promising strategy.

Species of Aspergillus section Flavi are recognized for their ability to produce metabolites, such as mycotoxins and organic acids. Kojic acid has gained widespread recognition in the cosmetics market for its efficacy in lightening skin blemishes. The importance of these species makes their correct identification and preservation essential. This study aimed to re-identify, taxonomically, Aspergillus section Flavi strains stored at the URM culture collection (WDCM 604) in Brazil and to investigate their potential for kojic acid production. Initially, 194 Aspergillus section Flavi strains were reactivated and authenticated based on DNA sequences ( CaM and BenA ). Furthermore, 99 strains were evaluated on synthetic solid medium to verify their ability to produce kojic acid. A representative strain from each species was selected to evaluate kojic acid production via submerged fermentation, using sugarcane molasses and corn steep liquor as carbon and nitrogen sources, respectively. Quantitative analysis of kojic acid was performed by high-performance liquid chromatography. In submerged fermentation, Aspergillus caelatus URM 4242 showed the highest production (10.65 ± 0.4 g/L with a yield of 0.54 g/g). Our results highlight the importance of culture collections, taxonomic re-identification, and assessment of the biotechnological potential of strains deposited in these biobanks.