Background and aims – The present study aims to describe a new species of pennate blue diatom from the genus Haslea, H. nusantara sp. nov., collected from Semak Daun Island, the Seribu Archipelago, in Indonesian marine waters. Methods – Assessment for species identification was conducted using light microscopy, Scanning Electron Microscopy and molecular techniques. The morphological characteristics of H. nusantara have been described, illustrated and compared to other morphologically similar blue Haslea taxa, distributed worldwide. Additionally, molecular characterization was achieved by sequencing plastidial and mitochondrial genomes. Key results – This new species, named Haslea nusantara, cannot be discriminated by its morphology (stria density) but it is characterized by its gene sequences (rbcL chloroplast gene and cox1 mitochondrial gene). Moreover, it differentiates from other blue Haslea species by the presence of a thin central bar, which has been previously reported in non-blue species like H. pseudostrearia. The complete mitochondrion (36,288 basepairs, bp) and plastid (120,448 bp) genomes of H. nusantara were sequenced and the gene arrangements were compared with other diatom genomes. Phylogeny analyses established using rbcL indicated that H. nusantara is included in the blue Haslea cluster and close to a blue Haslea sp. found in Canary Islands (H. silbo sp. ined.). Conclusions – All investigations carried out in this study show that H. nusantara is a new blue-pigmented species, which belongs to the blue Haslea clade, with an exceptional geographic distribution in the Southern Hemisphere.

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Desa Bakau is located in Sambas Regency, West Kalimantan which has the potential for mangrove forests with an area of ± 305 Ha. Ecologically, mangrove forests have various roles, one of them is as a habitat for various types of aquatic biota, including gastropods. Several gastropods have important economic value for the community as food and medicine. The local community catches and consumes the mangrove gastropods. As a food ingredient, gastropods have a high nutritional content and essential macro minerals. Gastropods can be used as an alternative source of animal protein at an affordable price. This study aimed to determine the nutritional value of the gastropod Cassidula from the mangrove area of Desa Bakau, Sambas Regency, West Kalimantan. Quantitatively, nutrient content such as protein, carbohydrates, fat, moisture, and ash content were determined according to the AOAC (2005) standard method, whereas macro minerals content (Na, K, Mg, Ca, and P) was carried out according to the AOAC method (2016) using Atomic Absorption Spectroscopy (AAS). The result showed that Cassidula had a protein content (57.02%) with the highest value compared to other types of nutrients. In addition, Cassidula also contained an essential macro mineral, such as calcium (37.0006 mg/kg) with the highest value followed by sodium (21.7364 mg/kg), respectively. The results showed that Cassidula can be used as an alternative food ingredient for human.

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Sargassum policystum is one of the genus Sargassum from the brown macroalgae group which has an abundance of chemical constituents of fucoidan, fucoxanthin, phenolic acids and alginate which have important biological activities, such as antioxidants and antibacterials. This species thrives in the waters of Kabung Island, Bengkayang, West Kalimantan and has not been exploited so that it tends to act as a marine weed. This study aimed to determine the total phenolic content of the ethanolic extract of S. policystum and its antioxidant and antibacterial activity. Determination of the total content of phenolic compounds using the Folin Ciocalteu method, antioxidant testing using the DPPH method (2,2-diphenyl-1-picrylhydrazyl) and the indicator of sample color change with the addition of these radicals was measured by UV-Vis spectrophotometer. Antibacterial testing was carried out by the test sample diffusion method and the inhibition of the growth of the test bacteria Staphylococcus aureus and Escherichia coli as test bacteria was indicated by the formation of a clear area around the sample wells. The results showed that the phenol content of the ethanolic extract of S. policystum was 79.8 mg/g extract, its antioxidant activity (IC50) was 98.903 ppm, classified as a strong antioxidant, while the comparison antioxidant, Vitamin C, had an IC50 of 6.26 ppm. The inhibitory ability of the ethanol extract against the test bacteria used was indicated by the formation of the largest inhibition diameter on S. aureus of 12.4 mm and E. coli of 12.0 mm.

The diatom Haslea ostrearia was first studied by Gaillon in the year 1820 because of the greening phenomenon of oysters in western France. This microalga has the capacity to produce and excrete a blue pigment, called marennine, that has antioxidant, anti-bacterial and anti-viral properties, with possible industrial applications related to aquaculture and cosmetics. However, it is difficult to produce biomass in large concentrations in photobioreactors (i.e, usually 1 kg m −3 dry weight or higher) due to stirring sensitivity, and also because diatoms have special requirements, such as a supply of silica. This work presents a design for a new, completely artificial, seawater medium named NX (i.e, Nghiem Xuan) for optimizing cultivation of the diatom H. ostrearia in photobioreactors. NX takes account of the carbon and phosphorus sources in either organic or inorganic form, and the composition of the main elements (C, H, O, N, P, S, Si). Optimization of the calcium, magnesium and iron concentrations was found to be essential in order to achieve the highest productivities. The resulting NX medium was validated in an airlift photobioreactor. This led to productivities of 4.9 × 10 8 cell L −1 (ca. 500 mg L −1 of biomass) and 15.7 mg L −1 of marennine, higher than has previously been reported in the literature.

Free radicals contribute to human health problem resulting in various human diseases, including central nervous system injury, cancer, inflammations, and the decrease of organ function related to oxidation. This condition has encouraged the effort of finding new natural antioxidant and anti-inflammatory sources. Macroalgae act as excellent natural resources due to their bioactive potential with diverse applications in various fields. Eucheuma cottonii belonging to Rhodophyceae grow abundantly along Lemukutan Island waters, however, their existence has not been exploited. This study aims to evaluate antioxidant and anti-inflammatory activities of ethanol extract of E. cottonii from Lemukutan Island waters, West Kalimantan. The observation of antioxidant activity was done using the method of DPPH (1,1-diphenyl-2-picrylhydrazyl) with UV-vis spectrophotometer, while anti-inflammatory acyivity activity was determined using the RBCs membrane stability method. The ethanolic extract of E. cottonii had potential antioxidant activity with IC50 of 127.75 ppm and was classified as moderate category. Extracts showed also anti-inflammatory acyivity activity with the concentration of 219.83 ppm. Red macroalgae E. cottonii can be used as potential natural antioxidant and anti-inflammatory agent.

Kesehatan adalah salah satu berkah yang sangat berharga dalam kehidupan. Kondisi pandemi Covid-19 telah melahirkan budaya 3M dalam kehidupan sehari-hari, yaitu memakai masker, menjaga jarak dan mencuci tangan. Mencuci tangan menggunakan handsanitizer merupakan cara yang praktis untuk membunuh mikroorganisme. Namun, handsanitizer yang tersedia di pasaran memiliki variasi bahan baku yang mengandung Alkohol 96% dan peroksida. Pemakaian yang sering dan dalam jangka waktu yang lama dapat memberikan efek samping iritasi pada kulit tangan. Selain itu, upaya lain untuk menjaga kebersihan lingkungan dapat dilakukan dengan menggunakan larutan desinfektan. Larutan ini dapat membebaskan lantai, dinding rumah, peralatan rumah tangga, dan udara sekitar dari mikroorganisme. Namun, desinfektan umumnya mengandung komponen kimia yang sangat korosif. Oleh karena itu, kondisi ini mendorong pencarian sumber bahan ramah lingkungan. Pelatihan ini bertujuan untuk meningkatkan kesehatan masyarakat Teluk Batang secara mandiri melalui pembuatan handsanitizer dan desinfektan berbasis eco-enzyme dari limbah sayuran dan buah. Eco-enzyme dibuat dari  5kg  sampah campuran sayur dan buah yang difermentasi selama 3 bulan, dihasilkan cairan enzim sebanyak 9 kg  dan ampas fermentasi sebanyak 6 kg. Kemudian, handsanitizer diproduksi menggunakan rasio 10% : 40% dengan mencampur 100 mL eco-enzyme dan 400 mL air bersih. Sedangkan larutan desinfektan dibuat menggunakan rasio 50% : 50% dengan mencampur 250 mL eco-enzyme dan 250 mL air bersih. Produk yang dihasilkan kemudian diberi label dan dapat digunakan langsung oleh peserta pelatihan.