Spirulina maxima is a marine microalga that has been promoted worldwide as a super food. This study was conducted to evaluate its ability to improve memory in the older adults using Spirulina maxima 70% ethanol extract (SM70EE). This randomized, double-blind, placebo-controlled clinical trial comprised 80 volunteers recruited from Jeonbuk National University Hospital in Jeonju, Republic of Korea, who were randomly assigned to two groups. The participants received either 1 g/day of SM70EE or a placebo without otherwise changing their diet or physical activity. The participants were examined at baseline and after a 12-week interval to determine whether there were changes in their results for visual learning, visual working memory, and verbal learning tests from the Korean version of the Montreal Cognitive Assessment, brain-derived neurotrophic factor and beta-amyloid levels, and total antioxidant capacity. Compared to the placebo group, the treatment group showed a significant improvement in visual learning and visual working memory test results and enhanced vocabulary. SM70EE use was shown to improve memory, with no adverse effects. Its efficacy in alleviating Alzheimer’s disease symptoms was verified for the first time through this clinical trial. SM70EE could play a role in the management of patients with dementia. This trial is registered with registration number of clinical research information service (CRIS: KCT0006161).

There is increasing demand for essential fatty acids (EFAs) from non-fish sources such as microalgae, which are considered a renewable and sustainable biomass. The open raceway system (ORS) is an affordable system for microalgae biomass cultivation for industrial applications. However, seasonal variations in weather can affect biomass productivity and the quality of microalgal biomass. The aim of this study was to determine the feasibility of year-round Tetraselmis sp. cultivation in a semi-ORS in Korea for biomass and bioactive lipid production. To maximize biomass productivity of Tetraselmis sp., f medium was selected because it resulted in a significantly higher biomass productivity (1.64 ± 0.03 g/L) and lower omega-6/omega-3 ratio (0.52/1) under laboratory conditions than f/2 medium (0.70/1). Then, we used climatic data-based building information modeling technology to construct a pilot plant of six semi-ORSs for controlling culture conditions, each with a culture volume of 40,000 L. Over 1 year, there were no significant variations in monthly biomass productivity, fatty acid composition, or the omega-6/omega-3 ratio; however, the lipid content correlated significantly with photosynthetic photon flux density. During year-round cultivation from November 2014 to October 2017, areal productivity was gradually increased by increasing medium salinity and injecting CO₂ gas into the culture medium. Productivity peaked at 44.01 g/m²/d in October 2017. Throughout the trials, there were no significant differences in average lipid content, which was 14.88 ± 1.26%, 14.73 ± 2.44%, 12.81 ± 2.82%, and 13.63 ± 3.42% in 2014, 2015, 2016, and 2017, respectively. Our results demonstrated that high biomass productivity and constant lipid content can be sustainably maintained under Korean climate conditions.

This study is the first to show that increased mitochondrial activities improved the antiaging effects of Aloe vera leaf skin fermented by Lactobacillus plantarum on UV_b-irradiated skin fibroblasts. The fermented extract (AF) increased the activities of mitochondrial reductase and the complex II and significantly reduced reactive oxygen species (ROS) production, even under UV_b stress conditions, and also increased DPPH free radical scavenging activities compared with the hot water extract of outer layers of aloe leaf (AW) and quercetin itself. AF exerted a synergistic effect with quercetin and bioactive substances derived from the fermentation process. Moreover, mitochondrial activation of UV_b-irradiated human skin fibroblasts by 0.3% (w/v) of the AF plays important roles in increasing collagen production up to 125 ± 5.45% and decreasing MMP-1 secretion down to 69.41 ± 2.63% of the control levels. The AF enhanced the upregulation of collagen gene expression, and this change was also greater than those induced by the AW and quercetin. Therefore, this study concludes that fermentation of the skin of aloe leaves increases the activation of mitochondria and inhibits the photo-aging of UV_b-irradiated skin fibroblasts.

Sargassum fusiforme and Sargassum fulvellum are types of brown algae used for their nutritional value and medicinal properties, including anti-inflammatory, antioxidant, and anticancer effects. Despite their importance in various industries, many seaweed byproducts containing dietary fiber and polysaccharides are discarded in landfills. These byproducts can be recycled and repurposed for different applications. In this study, we investigated the impact of S. fusiforme food processing byproducts (MbP-SFF) and S. fulvellum food processing byproducts (MbP-SFV) on improving intestinal motility and reducing inflammation in mice with constipation induced by loperamide. To evaluate this, mice were orally administered 500 mg/kg/day of the byproducts once daily for 8 days. Constipation was induced by 5 mg/kg/day of loperamide for two days after oral administration for 6 days. Each sample contained approximately 70% carbohydrates. MbP-SFF had 52.0% mannuronic acid and 18.8% guluronic acid, while MbP-SFV had 36.9% mannuronic acid and 32.9% guluronic acid. These byproducts enhanced fecal excretion and intestinal motility by modulating inflammatory responses. Furthermore, they restored the balance of the gut microbiota disrupted by loperamide, increasing beneficial Bifidobacterium and reducing harmful Staphylococcus aureus. Overall, MbP-SFF and MbP-SFV improved intestinal motility and inflammation by influencing the gut microbiota and inflammatory responses in a loperamide-induced mouse model. These byproducts show potential as ingredients in functional foods aimed at enhancing gut health, potentially reducing waste disposal costs and addressing environmental concerns associated with their utilization.

Leptolyngbya sp. KIOST-1 has been proposed as a candidate species for use as a protein supplement due to its high protein content and absence of cytotoxicity. The species has also garnered attention due to the photosynthetic pigments it possesses. However, limited information is available on its cultivation. Therefore, this study was conducted to identify the optimal culture medium and fundamental physiological properties of Leptolyngbya sp. KIOST-1 under various culture conditions. In this study, SOT (Society of Toxicology) medium was confirmed as the optimal culture medium for Leptolyngbya sp. KIOST-1 growth. The biomass production, protein content, and photosynthetic pigment content of Leptolyngbya sp. KIOST-1 were significantly higher in SOT medium. The use of this medium allowed for scaling up from laboratory (10 mL) to pilot (200 L) conditions and industrial-scale outdoor conditions (10,000 L), with the biomass containing over 66% protein. The phytochemical composition of Leptolyngbya sp. KIOST-1 cultured at laboratory and industrial-scales was discovered in this study. Furthermore, we observed that reducing the carbon and nitrogen sources to 1/5 of those supplied by the optimal medium did not significantly affect biomass production, and Leptolyngbya sp. KIOST-1 demonstrated favorable growth capabilities in a salinity range of 10–50 psu and at pH levels of 8.3 to 10.3. The results of this study demonstrate the suitability of Leptolyngbya sp. KIOST-1 for various industrial applications and its adaptability to large-scale cultivation.

C-Phycocyanin (C-PC) is a photosynthetic pigment found in cyanobacteria, notably in Arthrospira species. The extraction of phycocyanobilin (PCB), the chromophore of C-PC, is a common approach to address the instability of C-PC under light, heat, and acidic conditions. Methanol is typically used for PCB extraction. However, its use poses challenges for industrial applications owing to the need for solvent removal, extensive purification, and safety validation. Therefore, this study proposes ethanol as an alternative to methanol, optimizing the ethanol extraction conditions through response surface methodology (RSM) using a central composite design (CCD) and techno-economic analysis. The parameters evaluated were the extraction temperature, time, and C-PC/solvent ratio. Optimal conditions—68.81 °C, 14.91 h, and a C-PC to solvent ratio of 1:95 (w/v)— yielded a predicted PCB yield of 29.18%, closely aligning with the actual value of 29.67 ± 1.33%. A techno-economic analysis for pilot-scale PCB production showed that optimized ethanol extraction could yield 147.13 kg/year with 506 batches, compared with 84.31 kg/year standard methanol extraction with 317 batches. Furthermore, it was evaluated to have a unit production cost of USD 1,413,588/kg, an internal rate of return (IRR) of 53.36%, and a payback time of 1.6 years with increased yields and reduced toxic solvent disposal costs. This study supports scalable PCB production with a natural blue pigment suitable for the food, beverage, and cosmetics industries.