Docosahexaenoic acid (DHA) production by Aurantiochytrium limacinum using cassava pulp hydrolysate as an alternative low-cost carbon source

Abstract

Cost of nutrients is one of the major contributors to the production cost of docosahexaenoic acid (DHA) by thraustochytrids, and this remains the main challenge for economical and sustainable production of DHA. In the present study, cassava pulp (CP) was investigated as an alternative low-cost carbon source for DHA production by Aurantiochytrium limacinum SR21. Cultivation conditions, i.e., salinity level, type of nitrogen source, and concentrations of glucose and nitrogen sources, as well as pH, were optimized for cell growth. CP was enzymatically hydrolyzed, and used as the base medium, supplemented with artificial seawater salts, for DHA production under fed-batch cultivation. A. limacinum grew well at 18 g/L of NaCl (equivalent to 50% salinity level), and initial glucose concentration of 64 g/L, initial yeast extract concentration of 5 g/L, and pH 7.5 were optimum for cell growth. Fed-batch cultivation, with dissolved oxygen (DO) controlled at 10%, using CP-based medium as the carbon source gave a final cell dry mass of 26.3 ± 2.0 g/L, with 15.5 ± 0.1 g/L of lipid. DHA content in the lipid was 37.4 ± 1.5%, equivalent to 5.8 ± 0.3 g/L, and DHA productivity was 960 mg/(L·d). Medium-based economic analysis showed that an economic yield (EY) of this process was 0.86, which was higher than the 0.81 obtained using glucose as the substrate, assuming the same process and conditions. Overall, the results reveal that CP is a highly feasible feedstock for DHA production by A. limacinum SR21.

PUFA and carotenoid producing thraustochytrids and their anti-microbial and antioxidant activities

“…The A. limacinum SR21 is recorded to produce the biomass of 3.4 ± 0.4 g L -1 , under fed-batch culture, while the same strain under optimized culture conditions is found to yield high biomass of 14.3 ± 0.5 g L -1 dry weight after 7 days of incubation (Aini et al, 2022). Hence, the optimization of culture conditions, and nutrient sources produce the maximum biomass of thraustochytrids.…”

“…Thraustochytrids have been investigated in various coastal, estuarine, and mangrove environments in different countries: China (Mohan et al, 2022), Vietnam (Hien et al, 2022), Thailand (Aini et al, 2022), Japan (Taoka et al, 2017), Sweden (Patel et al, 2021), Italy (Russo et al, 2021), Korea (Saini et al, 2023), and Taiwan (Chauhan et al, 2023). However, only a limited number of Indian mangrove areas is studied for thraustochytrids from Goa (Raghukumar, 2017), Kerala (Jaseera et al, 2018), Mumbai (Pawar et al, 2021), Andaman Islands (Kalidasan et al, 2021b), and Tamil Nadu (Kalidasan et al, 2021a).…”

The Clinical Promise of Microalgae in Rheumatoid Arthritis: From Natural Compounds to Recombinant Therapeutics

“…Several heterotrophic marine microorganisms are strong DHA producers, such as the dinoflagellate Crypthecodinium cohnii (Dinophyceae) and, above all, the thraustochytrids protists Thraustochytrium spp., Aurantiochytrium (formerly Schizochytrium) limacinum (Labyrinthulomycetes) [129][130][131][132][133], and related genera [134]. Although these microorganisms cannot exploit light energy to drive their metabolism, they are capable of fermenting plant biomass hydrolysates, affording cost-effective heterotrophic cultivation using renewable feedstocks [135][136][137][138][139][140][141]. Arguably, the most valuable heterotrophic sources of DHA are Schizochytrium spp., which recently obtained Novel Food status [142,143].…”