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This paper mainly focuses on the isolation and screening of actinomycetes from the south coast of Yogyakarta, which has bioactivity against plant pathogenic fungi. Actinomycetes with bioactivity against Phytophthora palmivora, a plant pathogenic fungus that causes fruit rot disease, was isolated and screened. The medium used for the isolation was starch casein mixed with antifungal compound of nystatin (25 µg/mL) and cycloheximide (75 µg/mL). The samples were pretreated by heating them for 15 minutes at 65℃. Bioactivity assay of the plant pathogenic fungi was conducted using the disc diffusion agar method. From the experiment, 36 isolates were obtained from 30 sediment samples. Two isolates, RS001.05, and RS003.04 showed inhibitory activity against the growth of the cocoa plant pathogenic fungi Phythopthora palmivora. RS001.05, which showed higher activity, was selected to be identified using DNA molecular identification. Microbial identification and characterization showed that RS.001.05 was actinobacteria, part of the genus Streptomyces, and part of the Streptomyces sp. with a homology was 99%. The phylogenetic tree showed that RS001.005 isolate was part of the same group as Streptomyces indonesiensis and Streptomyces malaysiensis. [ABSTRACT FROM AUTHOR]

Thraustochytrids is a family of microalga which lives in the marine ecosystem and mangrove habitats. Indonesia with a mangrove area of 3.49 million hectares, is a country with the largest mangrove habitats in the world. With such potency, the Indonesian mangrove has the largest Thraustochytrids habitat and it is hoped that the potency will attract Indonesian scientists to explore and develop a bio industry based on thraustochytrids. Thraustochytrids have potent biotechnology as a source of hydrolytic enzymes, carotenoids, squalene, biodiesel, and polyunsaturated fatty acids (PUFA), specifically docosahexaenoic acid (DHA). Among those biotechnology products, DHA is the most promising product to be commercialized. According to a number of studies, DHA is critical throughout all life stages from the need for fetal development, the prevention of preterm birth, and the prevention of cardiovascular disease to the improvements in the cognitive function and the eye health of adults and the elderly. A recent study showed that n-3 PUFA indirectly or directly modulated the gut microbiota which acts as a prebiotic. However, cost production for producing dry thraustochytrids is relatively expensive. One of the ways to reduce those costs in production is by using low-cost substrates. Recently, it is already possible to produce thraustochytrid on a commercial scale using low-cost substrate palm oil mill effluent (POME), so cost production of dry thraustochytrids became economically feasible. Indonesia, as the number one crude palm oil (CPO) producer of 44,5 million tons has the great opportunity to develop an industry base DHA. [ABSTRACT FROM AUTHOR]

Interest in using natural products as food preservatives has grown due to the demand for healthy foods with minimal levels of chemical additives that are safe for people and the environment. Lactobacilli have been proven to produce antimicrobial substances such as bacteriocins that can serve as food preservatives. The investigation and assessment of bacteriocin-producing lactic acid bacteria (LAB) from 'dadih' have been conducted. A total of 6 strains were isolated from Indonesian buffalo milk fermented products, namely 'dadih'. Six isolates were phenotypically identified as LAB. The selected strain, DH3.1 was molecularly identified using 16S rRNA as Lactobacillus plantarum and had homology 100% to Lactobacillus plantarum strain B2.1B. Moreover, isolation and characterization of a bacteriocin produced by L. plantarum DH3.1 have been conducted. The bacteriocin was isolated by 50% ammonium sulfate precipitation. Bacteriocin showed thermal stability when heated at below 100°C for 30 min, pH stability between pH 2.0 and 10.0, resistance to adding surfactants including tween 20, tween 80, triton X-100, Sodium Dodecyl Sulfate, and EDTA and sensitive to trypsin, proteinase-K, and pronase-E. The bacteriocin activity could be enhanced by adding Fe2+ and Mn2+ and inhibited by Zn2+, Mg2+, and K+. The study indicated that bacteriocin is promising to use in food preservation. [ABSTRACT FROM AUTHOR]

Oil palm basal stem rot caused by the plant pathogenic fungus Ganoderma boninense is a significant issue for plantation management in Indonesia. Since the use of chemical pesticides to eradicate G. boninense has proven ineffective and damaged the environment, biopesticides and biocontrol are needed to suppress the growth of G. boninense. This study aims to obtain potential microbes capable of suppressing and killing those plant pathogenic fungus. The isolation and screening of terrestrial actinomycetes isolated from soils of the oil palm plantation in Riau Sumatera have been conducted. RS25 isolate showed antifungal activity against the oil palm pathogenic fungus G. boninense. The antifungal agents' nystatin 25 mg/mL and cycloheximide 75 µg/mL have been added to the starch casein used for the isolation medium. Pretreatment of samples was also conducted by heating for 15 min at 65 ℃. Antifungal assay toward G. boninense was performed using the disc diffusion agar test. The result of the experiment has been obtained 16 isolates of actinomycetes from three soil samples. One isolate, RS25, showed inhibitory activity against G. boninense. Identification using 16S rRNA gene sequencing showed that RS25 belonged to the genus of Streptomyces, and the species of Streptomyces costaricanus with a homology value to strain K21C32 was 100%. [ABSTRACT FROM AUTHOR]