Alanine mother liquor as a nitrogen source for docosahexaenoic acid production by Schizochytrium sp. B4D1

Alanine mother liquor, a type of industrial waste from alanine fermentation, was used as a nitrogen source to produce docosahexaenoic acid (DHA) by Schizochytrium sp. B4D1. The results indicated that yeast extract could trigger the utilization of the alanine mother liquor. Additionally, the alanine can be quenched during the culture, which aids in DHA accumulation. The medium components were optimized via response surface methodology as follows: 99.98-g/L glucose, 0.05-g/L yeast extract and a 183.17 dilution factor of the alanine mother liquid (v/v, with an alanine content of 0.72 g/L) and 17.98% inoculum concentration (v/v). Finally, in a 50-mL shake-flask fermentation, the DHA yield was 2.29 g/L.

Expression of a Zika virus antigen in microalgae: Towards mucosal vaccine development.

Zika virus (ZIKV) infection has extended rapidly all over the world in the last decades affecting humans of all ages, inducing severe illness such as the autoimmune Guillain-Barré syndrome as well as fetal neurodevelopmental defects. Despite the epidemiological importance of ZIKV, today there are no commercially available drugs or vaccines to combat or prevent this infection. Microalgae are attractive hosts to produce and deliver vaccines, with some candidates under preclinical evaluation. Herein, algae-based expression was assessed for the production of a new vaccine candidate against ZIKV called ZK. The Algevir technology was applied to express an antigenic protein called ZK comprising the B subunit of the heat labile Escherichia coli enterotoxin along with 3 epitopes from the ZIKV envelope glycoprotein. Efficient expression of the ZK antigen was achieved in Schizochytrium sp. with yields of up to 365 µg g-1 microalgae fresh weight. Upon oral administration in mice, the microalgae-made ZK protein elicited significant humoral responses at a higher magnitude to those induced upon subcutaneous immunization. The algae-made ZK vaccine represents a promising candidate to formulate attractive vaccines against ZIKV.

Algevir: An Expression System for Microalgae Based on Viral Vectors.

The use of recombinant algae for the production of valuable compounds is opening promising biotechnological applications. However, the development of efficient expression approaches is still needed to expand the exploitation of microalgae in biotechnology. Herein, the concept of using viral expression vectors in microalgae was explored for the first time. An inducible geminiviral vector leading to Rep-mediated replication of the expression cassette allowed the production of antigenic proteins at high levels. This system, called Algevir, allows the production of complex viral proteins (GP1 from Zaire ebolavirus) and bacterial toxin subunits (B subunit of the heat-labile Escherichia coli enterotoxin), which retained their antigenic activity. The highest achieved yield was 1.25 mg/g fresh biomass (6 mg/L of culture), which was attained 3 days after transformation. The Algevir system allows for a fast and efficient production of recombinant proteins, overcoming the difficulties imposed by the low yields and unstable expression patterns frequently observed in stably transformed microalgae at the nuclear level; as well as the toxicity of some target proteins.

Effect of malate on docosahexaenoic acid production from Schizochytrium sp. B4D1

Background: Malate involves in the citrate/malate and transhydrogenase cycles to provide precursors for docosahexaenoic acid (DHA) synthesis. The optimal strategy was investigated for increasing DHA production in Schizochytrium species during fermentation. Results: DHA production increased by 47% and reached 5.51 g/L when 4 g malate/L was added during the rapid lipid accumulation stage in shake-flasks culture. Inducing effects of malate was further investigated through the analysis of three kinetic parameters, including specificcell growth rate(μ), specific glucose consumption rate (qGlu)and DHA formation rate (qDHA). DHA concentration was enhanced through a novel fed-batch strategy to a maximum value of 30.7 g/L, giving a yield of 0.103 g DHA/g glucose and a productivity of 284 mg L-1 h-1. Conclusion: A novel malate feeding strategy was developed that enhanced DHA yield and productivity of Schizochytrium species which may offer a desirable method for industrial applications.

Metabolite profiling of Schizochytrium sp. by GC-MS, an oleaginous microbial source of biodiesel.

The chemical screening carried out on Schizochytrium sp. biomass led the identification of 24 types of organic compounds belonging to n-alkanes, 1-alkenes, 1-alkanols, free fatty acids, methyl and ethyl esters of saturated and unsaturated fatty acids, saturated tri- and diglycerides, unsaturated monoglycerides, wax esters, sterols, triterpenes, and mono- and sesquiterpenes. Moreover, a sample containing fully saturated ethyl biodiesel was obtained experimentally with a yield of 28.72% w/w of the crude extract, and an average chain length of 15.52 carbons. This strain produced no toxins, but showed important nutrients, making it potentially applicable to the field of functional food, and biodiesel production.

Metabolite profiling of Schizochytrium sp. by GC-MS, an oleaginous microbial source of biodiesel

The chemical screening carried out on Schizochytrium sp. biomass led the identification of 24 types of organic compounds belonging to n-alkanes, 1-alkenes, 1-alkanols, free fatty acids, methyl and ethyl esters of saturated and unsaturated fatty acids, saturated tri- and diglycerides, unsaturated monoglycerides, wax esters, sterols, triterpenes, and mono- and sesquiterpenes. Moreover, a sample containing fully saturated ethyl biodiesel was obtained experimentally with a yield of 28.72% w/w of the crude extract, and an average chain length of 15.52 carbons. This strain produced no toxins, but showed important nutrients, making it potentially applicable to the field of functional food, and biodiesel production.

Metabolite profiling of Schizochytrium sp. by GC-MS, an oleaginous microbial source of biodiesel

The chemical screening carried out on Schizochytrium sp. biomass led the identification of 24 types of organic compounds belonging to n-alkanes, 1-alkenes, 1-alkanols, free fatty acids, methyl and ethyl esters of saturated and unsaturated fatty acids, saturated tri- and diglycerides, unsaturated monoglycerides, wax esters, sterols, triterpenes, and mono- and sesquiterpenes. Moreover, a sample containing fully saturated ethyl biodiesel was obtained experimentally with a yield of 28.72% w/w of the crude extract, and an average chain length of 15.52 carbons. This strain produced no toxins, but showed important nutrients, making it potentially applicable to the field of functional food, and biodiesel production.