Astaxanthin is a valuable carotenoid pigment, which has been extensively used in various industries. In this study, Rhodosporidium toruloides was first used as a new microbial source for producing natural astaxanthin. Various carbon, nitrogen, and mineral sources were evaluated for their effect on astaxanthin production of R. toruloides. Response surface methodology (RSM) was then used to optimize the medium compositions for maximizing the astaxanthin concentration. Among the examined nutrients, glucose, peptone, and KH2PO4 were the most efficient carbon, nitrogen, and mineral source for astaxanthin production, respectively. Through RSM, a maximum astaxanthin concentration of 927.11 µg l-1 was obtained by using Hansen broth containing 83.74 g l-1 glucose, 20.01 g l-1 peptone, and 6.19 g l-1 KH2PO4. This study suggested that R. toruloides is a promising candidate to produce natural astaxanthin.

The conversion of organic wastes into biodiesel has become an attractive solution to address waste surplus problems and energy depletion. Oleaginous insects can degrade various organic wastes to accumulate fat-based biomass, thus serving as a potential feedstock for biodiesel production. Therefore, the use of insects fed on organic waste for biodiesel production has increasingly attracted considerable investigations. In recent years, different insect species have been studied for their efficiency in converting various organic wastes and for producing biodiesel from their fat. Several methods have been developed for biodiesel production from insects to improve yields and reduce production costs and environmental impacts. This review summarizes the latest findings of the use of insects for converting organic wastes into biodiesel. The production processes and fuel properties of biodiesel produced from insects are also discussed.

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Rhodosporidium toruloides strain VN1 is of special interest because of its capability for high astaxanthin production. Here, we report the draft genome sequence of R. toruloides VN1, which comprises 20.01 Mb in 424 contigs with an overall G + C content of 61.8%. This whole-genome shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession number SJTE00000000.

Astaxanthin is a valuable carotenoid, which has been approved as a food coloring by the US Food and Drug Administration and is considered as a food dye by the European Union (European Commission). This work aimed to attain Rhodosporidium toruloides mutants for enhanced astaxanthin accumulation using ultraviolet (UV) and gamma irradiation mutagenesis. Gamma irradiation was shown to be more efficient than UV for producing astaxanthin-overproducer. Among the screened mutants, G17, a gamma-induced mutant, exhibited the highest astaxanthin production, which was significantly higher than that of the wild strain. Response surface methodology was then applied to optimize the medium compositions for maximizing astaxanthin production by the mutant G17. The optimal medium compositions for the cultivation of G17 were determined as a peptone concentration of 19.75 g/L, malt extract concentration of 13.56 g/L, and glucose concentration of 19.92 g/L, with the maximum astaxanthin yield of 3021.34 µg/L ± 16.49 µg/L. This study suggests that the R. toruloides mutant (G17) is a potential candidate for astaxanthin production.