Polyunsaturated fatty acids production by solid-state fermentation on polyurethane foam by Mortierella alpina

Polyunsaturated fatty acids (PUFAs) are essential in healthy diets and their production is extremely important. Natural sources of PUFAs includes animal and aquatic products such as marine fish oil, however there are several limitations such as the decrease of fish stocks throughout the world. Thus, microbial oils are a preferable source of PUFAs. Herein, it was studied the production of PUFAs by Mortierella alpina under solidstate fermentation (SSF) using polyurethane foam as inert substrate and synthetic medium or lignocellulosic hydrolysate as source of C, N and other nutrients. Several parameters of fermentation conditions were evaluated as carbon source, inductors addition, ratio C/N and temperature. The highest amount of total PUFAs per mass of solid (535.41 ±24.12 mg/g), linoleic acid (129.66 ±5.84 mg/g) and linoleic acid (401.93 ±18.10 mg/g) were produced when the culture medium contained 20 g/L glucose, 10% (w/v) linseed oil, the C/N ratio was adjusted to 25 and the incubation temperature was 25 °C for 3days decreasing to 16 °C on the remaining 4days of fermentation. In addition, a hemicellulosic hydrolysate can be used as lowcost substrate to produce PUFAs, although the production was lower than the achieved with synthetic medium. SSF showed an interesting technology for microbial PUFAs production.José Manuel Salgado was supported by grant CEB/N2020— INV/01/2016 from Project “BIOTECNORTE—Underpinning Biotechnology to foster the north of Portugal bioeconomy” (NORTE 01-0145-FEDER-000004). This work was supported by the R&D&I project “Development of innovative sustainable protein and omega-3 rich feedstuffs for aquafeeds, from local agro-industrial by-products”, reference POCI-01-0145-FEDER-030377, funded by European Regional Development Fund (ERDF). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTec-Norte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Calcification responses of symbiotic and aposymbiotic corals to near-future levels of ocean acidification

Increasing the acidity of ocean waters will directly threaten calcifying marine organisms such as reef-building scleractinian corals, and the myriad of species that rely on corals for protection and sustenance. Ocean pH has already decreased by around 0.1 pH units since the beginning of the industrial revolution, and is expected to decrease by another 0.2–0.4 pH units by 2100. This study mimicked the pre-industrial, present, and near-future levels of <i>p</i>CO₂ using a precise control system (± 5% <i>p</i>CO₂), to assess the impact of ocean acidification on the calcification of recently settled primary polyps of <i>Acropora digitifera</i>, both with and without symbionts, and adult fragments with symbionts. The increase in <i>p</i>CO₂ of ~100 μatm between the pre-industrial period and the present had more effect on the calcification rate of adult <i>A. digitifera</i> than the anticipated future increases of several hundreds of micro-atmospheres of <i>p</i>CO₂. The primary polyps with symbionts showed higher calcification rates than primary polyps without symbionts, suggesting that: (i) primary polyps housing symbionts are more tolerant to near-future ocean acidification than organisms without symbionts, and (ii) corals acquiring symbionts from the environment (i.e., broadcasting species) will be more vulnerable to ocean acidification than corals that maternally acquire symbionts