Often isolated from soil-dwelling microbes such as Serratia marcescens and Streptomyces coelicolor, red-pigmented prodigiosin and its derivatives have been characterized as natural bioactive compounds which possess a broad range of cytotoxic activity against various cancer cell lines as well as other biology activities. The raising need to enhance the production of this secondary metabolite due to its wide applications in both industrial and therapeutic field has gained attention from researchers over decades. Several approaches were carried out ranging from improving nutrient sources to metabolic engineering of S.coelicolor or co-cultivation with other bacteria. Recently, studies reported cell-free supernatant from lactic acid bacteria (LAB) intensively stimulated the pigment production from Streptomyces colelicor, however the reason for this enhancement was still unknown. In this study, we further investigated on the effect of lactic acid, a bioactive compound extracted from cell-free supernatants of LAB on prodigiosin production from Streptomyces coelicolor. The resulted data with 2 different strains of lactic acid bacteria (Leuconostoc mesenteroides and Lactobacillus plantarum) revealed treatment with lactic acid isolated from LAB exhibited an inhibition effect on prodigiosin yield in both intracellular and extracellular extraction.
Lactic acid bacteria play a vital role in biosynthesis of γ -aminobutyric acid (GABA) in the presence of glutamic acid - major substrate for the process. In recent study, Lactobacillus fermentum A01 (L. fermentum A01) isolated from various sources in Vietnam were screened for bacteria strains with high efficiency in GABA formation. L. fermentum was cultured in MRS broth containing 25 mg/mL monosodium glutamate (MSG), at pH of 6.5 and incubated at the optimal conditions (37ºC, for 24, 48, 72 h). After extraction and thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) analysis, L. fermentum A01 showed the GABA yield about 1.34 mg/g in dried supernatant, suggesting L. fermentum A01 to be a promising GABA producer for food and pharmaceutical applications.
The ability of endophytic fungi to produce valuable bioactive compounds when surviving in medicinal herbs. Finding out endophytic fungi originated from Catharanthus roseus with antimicrobial, antioxidant and cytotoxicity activities is important for pharmaceutical development. The isolation was based on the morphology of fungi. Identification was performed by sequencing 18S rRNA that was compared with known genes using Blast search in the combination of phylogenic analysis by using Clustal W and PhyML in GenomeNet. For the antimicrobial test, the agar diffusion method was used. DPPH scavenging assay for the antioxidant activity determination by using spectrophotometry. The cytotoxicity test was carried out by Sulforhodamine B method. LC-MS was applied for predicting components. We isolated the Fusarium oxysporum F01 strain originated from Catharanthus roseus. The aqueous extracts showed inhibition against Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853 (15.00 ± 0.50 mm), Serratia marcescens ATCC 14756 (9.00 ± 0.87 mm), Vibrio parahaemolyticus ATCC 17802 (15.50 ± 0.87 mm), Escherichia coli ATCC 25922 (12.50 ± 0.50 mm). The antioxidant activity of the extract obtained from the supernatant was determined with an IC50 value of about 11 µg/mL. The extract also showed cytotoxicity effect on liver cancer cell line (HepG2) and breast cancer cell line (MCF-7) with the percentage of inhibition of 84.47 ± 3.18 and 94.69 ± 1.59, respectively. LC-MS was used to point out the presence of pratol, a melanogenesis agent. The study provided more interesting information about Fusarium oxysporum F01 isolated in Catharanthus roseus grown in Vietnam, contributing to pharmaceutical sources in the world.
In the study, Bacillus megaterium T04 isolated from Rach Lang stream in Vietnam was identified. The stream samples were diluted in 0.9 % NaCl broth and then spread onto the ISP4 supplemented with rice and wheat starch. The colonies showed the strongest hydrolyzing activity were picked up and identified by biochemical test and 16S rRNA sequencing analysis. The starch hydrolyzing ability of this strain was detected by starch agar plate method. For maximum α-Amylase production, including 174.7 IU/ml and 0.2 IU/ml in medium containing wheat and rice, respectively was obtained after 72 h of incubation. The enzyme still showed high activity in 60% ammonium sulfate that was necessary for study on the enzyme characteristics. As a result, Bacillus megaterium T04 could produce high yield of amylase in simple conditions.
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