Production of Fungal Biomass for Feed, Fatty Acids, and Glycerol by Aspergillus oryzae from Fat-Rich Dairy Substrates

Abstract

Dairy waste is a complex mixture of nutrients requiring an integrated strategy for valorization into various products. The present work adds insights into the conversion of fat-rich dairy products into biomass, glycerol, and fatty acids via submerged cultivation with edible filamentous fungi. The pH influenced fat degradation, where Aspergillus oryzae lipase was more active at neutral than acidic pH (17 g/L vs. 0.5 g/L of released glycerol); the same trend was found during cultivation in crème fraiche (12 g/L vs. 1.7 g/L of released glycerol). In addition to glycerol, as a result of fat degradation, up to 3.6 and 4.5 g/L of myristic and palmitic acid, respectively, were released during A. oryzae growth in cream. The fungus was also able to grow in media containing 16 g/L of lactic acid, a common contaminant of dairy waste, being beneficial to naturally increase the initial acidic pH and trigger fat degradation. Considering that lactose consumption is suppressed in fat-rich media, a two-stage cultivation for conversion of dairy waste is also proposed in this work. Such an approach would provide biomass for possibly feed or human consumption, fatty acids, and an effluent of low organic matter tackling environmental and social problems associated with the dairy sector.

Evaluation of Filamentous Fungal Biomass Cultivated on Vinasse as an Alternative Nutrient Source of Fish Feed: Protein, Lipid, and Mineral Composition

“…The results of the evaluated parameters that made considerable changes in the biomass yield (including medium concentration and cultivation pH) are tabulated in Table 2. Other parameters, such as the optimum cultivation temperature for each species and shaking rate, were previously investigated, and the optimal cultivation conditions were applied in the current study based on Mahboubi Soufiani et al [41]. According to the collected data (Table 2), the 95% diluted (v/v) vinasse supports the best growth for A. oryzae, N. intermedia, and R. oryzae.…”

“…A. oryzae was able to utilize glycerol as a carbon source. When a nitrogen source, such as yeast extract, was present in the cultivation medium, A. oryzae could assimilate 25.6 g/L of the total 27 g/L available glycerol during a 96 h cultivation period [41].…”

“…However, from the perspective of protein content, our fungal species showed an opposite order of importance. The constituents and nutritional properties of the fungal biomass are significantly related to the cultivation medium and conditions [41]. It was observed that vinasse has a good potential to support lipid deposition in fungal biomass.…”

Lead soaps formation and biodiversity in a XVIII Century wax seal coloured with minium

“…This hypothesis is not currently supported by the results, and all the lead soaps documented on ageing pigments were associated with chemical degradation so far (Schrenk, 1994); however, a biological involvement could be tested in future using model samples with a known composition and specially standardized microbial inoculations. Actually, many microorganisms are capable of producing fatty acids and glycerol as by-products of lipid metabolism (Leone and Breuil, 1999;Mahboubi et al, 2017).…”

Use of Organic Wastes and Industrial By-Products to Produce Filamentous Fungi with Potential as Aqua-Feed Ingredients

“…These compounds have important structural and functional duties in the fungal cell membrane and are one of the main energy sources for cell metabolism. Fungi can produce and secrete lipases that have the capacity to degrade substrate lipids and oils and produce free fatty acids and glycerol from triacylglycerols (TAG) [97]. Mitra et al [91] and Liang et al [30] described the ability of different fungal species in valuable nutritional oil production.…”