Zinc-solubilizing bacteria can convert the insoluble form of zinc into soluble forms available to plants. This study was conducted to isolate and screen zinc-solubilizing actinobacteria from rhizosphere soils and to assess their effect on vegetable soybean growth. In total, 200 actinobacteria strains belonging to 10 genera were isolated from rhizosphere soil samples. Among these isolates, four showed zinc solubilization with solubilizing index values ranging from 3.11 to 3.78 on Bunt and Rovira agar supplemented with 0.1% zinc oxide. For the quantitative assay, in broth culture, strains CME34 and EX51 solubilized maximum available zinc contents of 529.71 and 243.58 μg/ml. Furthermore, indole-3-acetic acid (IAA) and ammonia were produced by these two strains, the strain CME34 produced the highest amount of IAA 4.62 μg/ml and the strain EX51 produced the highest amount of ammonia 361.04 μg/ml. In addition, the phosphate-solubilizing abilities in Pikovskaya’s medium of CME34 and EX51 were 64.67 and 115.67 μg/ml. Based on morphological and biochemical characterization and 16S rDNA sequencing, the strains CME34 and EX51 were closely related to the genus Streptomyces . In a greenhouse experiment, single-strain inoculation of Streptomyces sp. CME34 or EX51 significantly increased the shoot length, root length, plant dry weight, number of pods per plant and number of seeds per plant of vegetable soybean plants compared to the uninoculated control. These findings facilitated the conclusion that the two Streptomyces strains have potential as zinc solubilizers and can be suggested as bioinoculants to promote the growth and yield of soybean.

Dracaena cochinchinensis (Lour.) S.C. Chen (Chandaeng) is an important traditional medicinal plant used in ancient Thai household remedies. This research focused on investigating the biological properties, including the antibacterial, anti-tyrosinase, antioxidant activities, and phytochemical characteristics of crude Chandaeng extracts. Dried Chandaeng heartwood powder was extracted using ethanol, methanol, and deionized water. The antibacterial activities of the extracts were then tested against skin pathogens, including Cutibacterium acnes (DMST14916), Staphylococcus epidermidis (TISTR518), and Staphylococcus aureus (TISTR321). The ethanolic extract showed antibacterial activity. In a time-kill assay, all bacteria were completely killed after being exposed to it, while the cell membranes were found to have leaked when viewed under a scanning electron microscope. Antioxidant potential was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2¢-azino-bis -3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. According to the findings, the crude ethanolic extract of Chandaeng showed the highest level of antioxidant activity. Furthermore, the potential of the extract to treat skin hyperpigmentation by inhibiting tyrosinase, an important melanin synthesis enzyme, was determined and the ethanolic extract was found to be an anti-tyrosinase agent. Finally, the crude ethanolic extract showed the highest total phenolic compound and flavonoid content. In conclusion, crude Chandaeng extract showed significant potential in activity against skin pathogenic bacteria, antioxidant activity, and tyrosinase inhibition. These properties of the extract could be applied to skincare cosmetics.