The purpose of this study was to evaluate the antioxidant, antibacterial, and anti-UVB of three kinds of fermented fruit peel extracts by pectinase enzyme, including pomegranate, pomelo, and banana peel. The antioxidant was evaluated by the DPPH (2,2-Diphenyl-1-picrylhydrazyl) free radical scavenging method. Antibacterial activity against Escherichia coli and Staphylococcus aureus was assessed by disk diffusion assay, and the photoprotective activity was measured using a photospectrometric method. The results revealed that pomegranate peel extract at 3000 IU/g peel exhibited potent free radical scavenging property against DPPH, with the smallest IC₅₀ value at 0.18%, which was better than that of pomelo peel extract at 55.79%. Furthermore, the results suggested that the pomegranate peel extract also exhibited antibacterial activity against E. coli better than pomelo peel extract, but none of the three samples shows the antibacterial capacity against S. aureus. Moreover, 10% pomegranate peel extract also expressed the strongest anti-UVB activity, with an SPF value of 36.582. The research demonstrates pomegranate peel’s bioactivity potential for further experiments.

Quach VCT, Tran QD, Ha NH, Nguyen BT, Tu TD, Nguyen PT. 2023. Antibacterial activity of lactic acid bacteria from various freshwater fish species against pathogenic bacteria in caged red tilapia (Oreochromis sp.). Biodiversitas 24: 3373-3383. Antibiotic-resistant bacteria are a big challenge for many aquaculture countries around the world. The search for new solutions, such as probiotics to replace antibiotics in aquaculture, attracts the interest of many scientists. The investigation was accomplished by isolating Lactic Acid Bacteria (LAB) inhibiting Streptococcus agalactiae and Aeromonas hydrophila, which cause swollen eyes and hemorrhagic skin disease in caged red tilapia (Oreochromis sp.) in Vinh Long province. The findings isolated 37 isolates of LAB from the intestines of catfish, red tilapia, and tilapia. Using the diffusion well method, the results showed that 13/37 (35.14%) and 18/37 (48.65%) isolates were inhibitory against S. agalactiae and A. hydrophila, respectively. The research found that eight isolates were inhibitory to two species of S. agalactiae and A. hydrophila, especially isolate CT6.2, which has the strongest inhibition (10.5 mm inhibition zone diameter). Our finding revealed that the isolates CT6.2 and RP6 demonstrate the highest antagonistic activity against S. agalactiae and A. hydrophila at a density of 108 CFU/mL after incubation at 35°C, pH = 5-6 for 48-60 h. Using PCR techniques and 16S rRNA gene sequencing combined with morphological and biochemical characteristics, the LAB isolates in the findings belong to the genera Lactobacillus and Pediococcus, being 99.35% and 99.02% similar to Lactobacillus plantarum and Pediococcus pentosaceus, respectively. This is the first report on the antimicrobial activity of LAB against S. agalactiae and A. hydrophila in caged red tilapia in the Mekong Delta.

Thuy NP, Nam NN, Trai NN, Thao NHX, Phong VT, Khang DT. 2022. Potential of Trichoderma spp. isolated in the rhizosphere to produce biofertilizer from organic materials. Biodiversitas 23: 6386-6396. Trichoderma spp. are filamentous fungi present in nearly all soils and capable of secreting large amounts of cellulase enzymes that can degrade carbohydrate polymer. In the current study, eight isolates of Trichoderma spp. (TC10-RL11, CT11-VO11, CN2-DP11, CN1-DP11, TC9-RL11, CN4-VR11, CK6-VC11, and TC8-RL11) were isolated. Among the eight fungal strains, the CN4-VR11 had highly potent CMC degradation with a halo’s diameter zone of 8.7 ± 1.5 cm. The BLAST result indicates that the CN4-VR11 strains and Trichoderma reesei had a similarity of 98.92% with a max score of 1158 and an E-value of 0.0. The Trichoderma reesei CN4-VR11 was selected for bioproduct production. The application of Trichoderma reesei CN4-VR11 bioproduct passively increased the efficient decomposition of the organic fertilizers, after only 30 days of incubation, the total organic matter content ? 20% was observed to be soft, spongy, and brown-back in color. According to the Government of Vietnam’s Decree No. 108/2017/ND-CP on fertilizer management, dated September 20, 2017, the T5 and T7 treatments were chosen for the production of granular bio-compost, which has a more practical use in agricultural land.

Effective water management plays an important role in socioeconomic development in the Vietnamese Mekong Delta (VMD). The impacts of climate change and human activities (that is, domestic consumption and industrial and agricultural activities) vary in different subregions of the delta. In order to provide intersectoral data for determining the significantly impacted subregions of the VMD, the present study simulated interactions between local climatic patterns, human activities, and water resources using a system dynamics modeling (SDM) approach with each subregion as an agent of the developed model. The average rainfall and temperature of 121 subregions in the VMD were collected during 1982–2012, and the future changes of climate by provinces were based on the Representative Concentration Pathways (RCP) scenarios (RCP4.5 and RCP8.5) by the end of 21st century. The assessment was based on the levels of impact of various factors, including (1) water consumption, (2) differences between evapotranspiration and rainfall, and (3) spatial distribution of salinity intrusion over the delta scale. In the coastal areas, as well as the central and upstream areas, water resources were projected to be affected by environmental changes, whereas the former, characterized by the lack of surface freshwater, would be affected at a greater scale during the dry season. Besides, the sea level rise would lead to an increase in negative impacts in the eastern coastal areas, suggesting that water-saving techniques should be applied not only for agriculture, but also for industry and domestic water consumption during the dry season. In addition, the south subregions (that is, the western subregions of the Hau River except for An Giang) were likely to be flooded due to the simulated high rainfall and seasonal rises of sea level during the wet season. Therefore, the alternative forms of settlement and livelihood should be considered toward balance management with changing delta dynamics.

The diversity in structure and herbicidal properties detected in natural phytotoxic compounds could bring about advantages for development bio-herbicides. The present study was carried out search for potential weed inhibitors from the parts of Mimosa pigra L. The ethyl acetate (EtOAc) extract of leaf of M. pigra showed inhibitory activity during the time that Echinochloa crus-galli (barnyardgrass) germinates and grows, which is greater than that of other extracts. From this active extract, potent growth inhibitors were isolated and identified by column chromatography (CC), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (¹H and ¹³C NMR). The six compounds were purified in this study namely: lupeol (C1, 13.2 mg), stigmastane-3,6-dione (C2, 14.7 mg), quercetin (C3, 20.2 mg), chrysoeriol (C4, 28 mg), methyl gallate (C5, 21.5 mg) and daucosterol (C6, 16.0 mg). The C2 (quercetin) compound completely inhibited the emergency, shoot height and root length of E. crus-galli at 1 mg/mL concentration (IC₅₀ shoot height = 0.56 mg/mL). This was also the first study to report the isolation and allelopathic activity of lupeol, chrysoeriol and daucosterol from M. pigra leaf. Findings of this study highlighted that quercetin from M. pigra may become bio-herbicide to control barnyard grass and other grass weeds for the development of safe agriculture.

Thuy NP, Trai NN. 2025. Composting domestic sewage using Trichoderma isolates were from agricultural soils. Biodiversitas 26: 1743-1753. This study aimed to evaluate the efficacy of Trichoderma spp. in enhancing the composting process of sewage sludge from domestic treatment plants. The research focused on improving organic matter decomposition and compost quality while addressing microbial safety. Thirteen Trichoderma isolates were screened from agricultural soils, with Trichoderma afroharzianum (isolate BCS3) identified as having the highest cellulase activity. Composting trials involved six treatments: one control, five sewage sludge combinations, and a T. afroharzianum BCS3 bioproduct. Parameters such as temperature, moisture content, pH, and the physicochemical and microbiological properties of the final compost were monitored throughout the 30-day process. All treatments completed the composting process with characteristic thermophilic phases. Treatment 3, featuring an optimal mix of sludge and T. afroharzianum BCS3 bioproduct, exhibited the most significant thermophilic activity, indicating enhanced microbial activity and rapid organic matter decomposition. Trichoderma-treated compost showed increased organic matter, improved nitrogen and phosphorus availability, and higher concentrations of humic substances. All composts met microbial safety standards, testing negative for E. coli and Salmonella. Trichoderma spp., particularly T. afroharzianum BCS3, significantly enhanced the composting of sewage sludge by accelerating organic matter breakdown and improving nutrient profiles. This sustainable approach offers an efficient solution for sludge management, producing high-quality organic fertilizer for agricultural use.