Sponge-associated fungi are attractive targets for the isolation of bioactive natural products with different pharmaceutical purposes. In this investigation, 20 fungi were isolated from 10 different sponge specimens. One isolate, the fungus Penicillium citrinum strain WK-P9, showed activity against Bacillus subtilis JH642 when cultivated in malt extract medium. One new and three known citrinin derivatives were isolated from the extract of this fungus. The structures were elucidated by 1D and 2D NMR spectroscopy, as well as LC-HRMS. Their antibacterial activity against a set of common human pathogenic bacteria and fungi was tested. Compound 2 showed moderate activity against Mycobacterium smegmatis ATCC607 with a minimum inhibitory concentration (MIC) of 32 µg/mL. Compound 4 exhibited moderate growth inhibition against Bacillus subtilis JH642, B. megaterium DSM32, and M. smegmatis ATCC607 with MICs of 16, 16, and 32 µg/mL, respectively. Furthermore, weak activities of 64 µg/mL against B. subtilis DSM10 and S. aureus ATCC25923 were observed for compound 4.

Marine bacteria produce natural pigments; however, the ability of marine bacterial symbionts to produce natural pigments has been less studied. Marine bacteria associated with soft-coral Sarcophyton sp. collected from Karimunjawa Island were successfully isolated and screened to synthesize the carotenoid pigments. This approach has allowed the use of these symbionts as an environmental friendly source of new natural pigments. Out of 33 bacterial isolates, only 4 bacterial symbionts (CBSCP 2-2, CBSCP 2-3, CBSCP 1-1, and CBSCP 2-4), positively contain carotenoid pigments. Molecular identification based on 16S rDNA method showed that bacterial symbionts CBSCP 2-2, CBSCP 2-3, CBSCP 1-1, and CBSCP 2-4 were closely related to Pseudoalteromonas shioyasakiensis, Pseudoalteromonas rubra, Virgibacillus salaries, and Pseudoalteromonas spongiae. Pigment analysis showed that the pigments have been categorized within the groups of carotenoid pigments. Antioxidant activity of pigment extracts was done by measuring inhibitory concentration (IC₅₀) of pigment extract against 2,2-diphenyl-1-picrylhydrazyl (DPPH) solution. The antioxidant activity measurement of CBSCP 1-1, CBSCP 2-2, CBSCP 2-3, and CBSCP 2-4 extract, and β-carotene was 2015, 5017, 2520, 4213, and 1980 mg l⁻¹, respectively.

The marine sponge Haliclona (Reniera) sp. was a potential source of natural bioactive compounds. This sponge widely distributed along the coast of Panjang Island, Jepara, Indonesia. The aims of this research were to isolate the associated bacteria with Haliclona (Reniera) sp. and to screen the antibacterial activity against Multi-Drug Resistant (MDR) bacteria. Amount five bacteria were isolated using media selective for bacteria. The antibacterial activities of bacteria were performed by overlay methods. The bacteria strain PSP. 39-04 had the best activity against Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacter baumannii, and Enterobacter cloaceae. Based on colony morphology and phylogenetic characterization using 16S rRNA gene sequencing, PSP 39-04 was closely related with Chromohalobacter salixigens strain DSM3043.

A coral-associated bacterium was successfully screened for secondary metabolites production based on PCR amplification of the nonribosomal peptide synthetase gene and was identified as closely related to Pseudoalteromonas luteoviolacea based on its 16S rDNA. The bacterium was found to inhibit the growth of shrimp pathogenic bacterium tested, Vibrio harveyi. To characterize the inhibiting metabolite, a 279 bp long DNA fragment was obtained and the deduced amino acid sequence showed conserved signature regions for peptide synthetases and revealed a high similarity to NosD (40% identity), a multifunctional peptide synthetase from Nostoc sp. GSV224, and NdaB (44% identity), a peptide synthetase module of Nodularia spumigen

Daphnia magna is a potential feed for fish. The aim of this research was to find the best treatment and effect of D. magna culture addition from fermented organic fertilizer, to growth and survival rate of Oreochromis niloticus larvae. There were five treatments, each with three repetitions used in the study. All treatments used chicken dung, and different combinations of rice bran, coconut oilcake waste and tilapia larvae. Feeding on tilapia was given by ad libitum method for five times a day until 14 days. Water quality during the research was maintained at temperature 28–29°C, DO 0.3 ppm and pH 8.1–8.2. Observed variables include relative growth rate, survival rate, food consumption rate and water quality. Our results showed that D. magna cultured by fermented organic fertilizer for tilapia larvae (O. niloticus) had high significant effect (p < 0.01) on the relative growth rate and survival rate. Treatment of D. magna cultured by 1.2 g/L chicken manure, 0.9 g/L rice bran and 0.3 g/L coconut oilcake showed the highest value on the relative growth rate (10.86%); survival rate (98.46%) and food consumption at first week (106.43%) and second week (152.76%)