This study aimed to compare the quality characteristics of pomegranate juice based on the extraction methods applied: centrifugal, single-gear, and twin-gear. Changes in the metabolic activities during digestion condition were further investigated. The twin-gear method was eventually identified as the optimal method, through comprehensive evaluation of the extraction rate, particle size, proximate composition, and the mineral and vitamin contents. Pomegranate juice derived using the twin-gear method had high-levels of bioactive substances such as phenolic compounds, flavonoids, anthocyanins, and selenium. Consequently, this juice exerted significant inhibitory effects on lipid peroxidation. Phenolic compounds are known to exhibit a high-correlation with skin-lightening, anti-aging, and anti-diabetic activities. An in vitro digestion model was used to evaluate changes in the antioxidant and angiotensin converting enzyme (ACE) inhibitory activities. Compared to levels observed before digestion, the results revealed a marked increase in the 2,2′azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging, ferric reducing antioxidant power, and superoxide dismutase-like activities as digestion progressed through the gastric phase condition, whereas most of these effects were stabilized or inhibited as digestion progressed through the intestinal phase. The ACE inhibitory activity was observed to increase after being subjected to gastric and intestinal digestion conditions. The correlation coefficients (r 2) for ACE inhibition and antioxidant activities were in the range 0.681∼0.952, thus indicating a highly positive correlation. The findings of this study indicate that the bioactivity of pomegranate juice is enhanced, as determined by the increase in various physiological activities as well as increase in the bioaccessibility and bioavailability of bioactive substances during digestion.

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The purpose of this study was to evaluate the antifungal activity, plant-growth-promoting activity, and mineral solubilization ability of 10 species of phytopathogenic fungi to select a Bacillus sp. from rhizosphere soils and roots that can be used as a microbial agent. The antifungal activity for phytopathogenic fungi varied based on the Bacillus sp. Among the selected strains, DDP4, DDP16, DDP148, SN56, and SN95 exhibited antifungal activity for nine or more species of phytopathogenic fungi. Regarding nitrogen-fixation ability, all Bacillus sp. showed similar levels of activity, and siderophore production ability was relatively high in ANG42 and DDP427. The indole-3-acetic acid production abilities were in the range of 1.83-67.91 µg/ ml, with variations in activity based on the Bacillus sp. One strain with a high activity was selected from each species, and their mineral solubilization abilities were examined. Most Bacillus sp. could solubilize phosphoric acid and calcium carbonate, and DDP148 and SN56 could solubilize silicon and zinc, respectively. These results suggested that Bacillus sp. can be considered potential multi-purpose microbial agents for plant growth promotion and disease prevention.

This study aimed to identify plant growth-promoting activity, phytopathogenic fungi growth inhibitory activity, mineral solubilization ability, and extracellular enzyme activity of the genus Bacillus in soil and the rhizosphere. With regards to antifungal activity against phytopathogenic fungi, DDP257 showed antifungal activity against all 10 pathogenic fungi tested. ANG20 showed the highest ability to produce indole-3-acetic acid, a plant growth-promoting factor (70.97 µg/ml). In addition, 10 species were identified to have 1-aminocyclopropane-1-carboxylate deaminase production ability, and most isolates showed nitrogen fixation and siderophore production abilities. Thereafter, the isolated strains' ability to solubilize minerals such as phosphate, calcite, and zinc was identified. With extracellular enzyme activity, the activity appeared in most enzymes. In particular, all the strains showed similar abilities for alkaline phosphatase, esterase (C4), acid phosphatase, and naphtol-AS-BI-phosphohydrolase production. This result was observed because the genus Bacillus secreted various organic substances, antibiotics, and extracellular enzymes. Therefore, through the results of this study, we suggest the possibility of using strains contributing to the improvement of the soil environment as microbial agents.

In this study, to select strains suitable as microbial agent from among rhizosphere microorganisms present in rhizosphere soil and roots, the mineral solubilization ability, antifungal activity against 10 types of plant pathogenic fungi, and plant growthpromoting activity of rhizosphere microorganisms were evaluated. As a result, DDP346 was selected because it has solubilization ability of phosphoric acid, calcium carbonate, silicon, and zinc; nitrogen fixing ability; production ability of siderophore, indole-3acetic acid, and aminocyclopropane-1-carboxylate deaminase; and antifungal activity against seven types of plant pathogenic fungi. DDP346 showed a 99.9% homology with Acinetobacter pittii DSM 21653 (NR_117621.1); phylogenetic analysis also revealed a close relationship with Acinetobacter pittii based on the 16S rRNA base sequence. The growth conditions of DDP346 were identified as temperatures in the range of 10-40 o C, pH in the range of 5-11, and salt concentrations in the range of 0-5%. In addition, a negative correlation coefficient (r 2 = −0.913, p <0.01) was shown between pH change and the solubilized phosphoric acid content of Acinetobacter sp. DDP346, and this is assumed to be due to the organic acid generated during culture. Consequently, through the evaluation of its mineral solubilization ability, antifungal activity against plant pathogenic fungi, and plant growth-promoting activity, the potential for the utilization of Acinetobacter sp. DDP346 as a multi-purpose microbial agent is presented.