Mycosporine-like amino acids (MAAs) are known as multifunctional natural compounds. The MAA mycosporine-2-glycine (M2G), isolated from the halotolerant cyanobacterium Aphanothece halophytica, has potential therapeutic applications for the prevention of skin ageing. Purified M2G was endotoxin-free. M2G had greater inhibitory activity of protein cross-linking compared with well-known inhibitor, aminoguanidine and hindered bacterial collagenase activity. The mechanisms for these inhibitory activities of M2G are discussed in this study.

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The maximum yield of xylanase from Aureobasidium melanogenum PBUAP46 was 5.19 ± 0.08 U ml −1 when cultured in a production medium containing 3.89% (w/v) rice straw and 0.75% (w/v) NaNO 3 as carbon and nitrogen sources, respectively, for 72 h. This enzyme catalyzed well and was relatively stable at pH 7.0 and room temperature (28 ± 2 °C). The produced xylanase was used to hydrolyze xylans from four tropical weeds, whereupon it was found that the highest amounts of reducing sugars in the xylan hydrolysates of cogon grass (Imperata cylindrical), Napier grass (Pennisetum purpureum), and vetiver grass (Vetiveria zizanioides) were at 20.44 ± 0.84, 17.50 ± 0.29, and 19.44 ± 0.40 mg 100 mg xylan −1 , respectively, but it was not detectable in water hyacinth (Eichhornia crassipes) hydrolysate. The highest combined amount of xylobiose and xylotriose was obtained from vetiver grass; thus, it was selected for further optimization. After optimization, xylanase digestion of vetiver grass xylan at 27.94 U g xylan −1 for 92 h 19 min gave the highest amount of reducing sugars (23.65 ± 1.34 mg 100 mg xylan −1 ), which were principally xylobiose and xylotriose. The enriched XOs exhibited a prebiotic property, significantly stimulating the growth of Lactobacillus brevis and L. casei by a factor of up to 3.5-and 6.5-fold, respectively, compared to glucose.

Extremophiles are a rich source of novel secondary metabolites and valuable antioxidative compounds. Here, we examined the antioxidative capacities of aqueous extracts derived from the halotolerant cyanobacterium Halothece sp. PCC7418. The antioxidative activities of extracts derived from Halothece sp. PCC7418 cells exposed to temperature shock were significantly enhanced. Quantification of antioxidant molecules (phenolic compounds and phycobiliproteins) in the aqueous extracts revealed that the amounts of these molecules were modulated by temperature shock. In addition, the intracellular accumulation of mycosporine-2-glycine, a potential antioxidative molecule, was strongly enhanced by cold shock. Our results show that the treatment of Halothece sp. PCC7418 cells with temperature shock may allow for the robust production of antioxidants.