Characteristics and Biological Activity of Exopolysaccharide Produced by Lysobacter sp. MMG2 Isolated from the Roots of Tagetes patula

Abstract

In the present study, exopolysaccharide (EPS) produced by Lysobacter sp. MMG2 (lyEPS) was characterized and purified. The lyEPS-producing strain Lysobacter sp. MMG2 was isolated from the roots of Tagetes patula. When lyEPS was produced in tryptic soy broth with 1% glucose and the lyophilized powder was measured, the yield was found to be 0.67 g/L. The molecular weight (Mw) of lyEPS was 1.01 × 105 Da. Its monosaccharide composition includes 84.24% mannose, 9.73% glucose, 2.55% galactose, 2.77% arabinose, 0.32% xylose, and 0.03% rhamnose. Scanning electron microscopy (SEM) revealed that lyEPS has various round and rough surfaces. Fourier-transform infrared (FTIR) analysis identified its carbohydrate polymer functional groups. Moreover, thermogravimetric analysis of lyEPS revealed two events of mass loss: the first was water loss, which resulted in 3.97% mass loss and the second event occurred at approximately 212 °C. lyEPS could inhibit biofilm-producing pathogenic bacteria without any antimicrobial activity. Furthermore, lyEPS at a concentration of 4 mg/mL could exhibit potent 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging activity (89.25%). These results indicate that lyEPS could be a promising candidate for industrial development if its biological activity is further explored.

Paraburkholderia tagetis sp. nov., a novel species isolated from roots of Tagetes patula enhances the growth and yield of Solanum lycopersicum L. (tomato)

“…The genomic DNA of strain RG36 T was extracted and PCR amplification and sequencing of 16S rRNA gene were performed as described previously ( Kim et al, 2022 ). The 16S rRNA gene was amplified using universal primers 27F, 518F, 805R, and 1492R; and the PCR products were commercially sequenced (Solgent, Daejon, Republic of Korea).…”

“…campestris KACC 10377 T which is responsible for black rot disease of crucifers. Another species of Lysobacter produced exopolysaccharide (EPS), that inhibited biofilm formation, exhibited remarkably high antioxidant activity, and had excellent thermostability ( Chhetri et al, 2022b ; Kim et al, 2022 ).…”

Nocardioides pini sp. nov. and Nocardioides pinisoli sp. nov., two novel actinomycetes isolated from Pinus densiflora

“…For the survey and investigation, a pine tree ( P. densiflora ) bacterial community root sample was collected from a park near Dongguk University, Goyang-si, Republic of Korea (37° 40′ 23.8″ N 126° 48′ 5.9″ E). For isolation, the rhizosphere soil was mixed with 5 ml of 0.85 % NaCl (w/v) sterile saline and serially diluted, from 10 −2 to 10 −4 , using a standard dilution method described previously [10]. A 100 µl aliquot of the sample suspensions was spread onto Reasoner’s 2A (R2A; Difco) agar plates and subsequently incubated at 30 °C for 5 days.…”

“…NaCl tolerance was tested on R2A agar containing various amounts of NaCl (0-3 %, at 1.0 % concentration intervals). Growth at various temperatures (4,10,15,20,25,28,30,35,37, 40 and 42 °C) was assessed on R2A agar. The hydrolysis of casein (2 % skimmed milk; Biopure), chitin (1 %; Sigma), carboxymethyl cellulose (1 % CM-cellulose; Duksan), DNA (DNase agar; MB Cell), starch (1 %; Sigma), Tween 20(1 %; Biopure) and Tween 80 (1 %; Biopure) was assessed as described by [11].…”

“…Additional biochemical tests for strain isolates and their reference strains were performed using API ZYM and API 20 NE kits according to the methods by the manufacturer (bioMérieux) under equivalent test conditions. Antibiotic sensitivity tests were performed using the following antibiotic discs (mg disc −1 ): cefazolin (30), ceftazidime (30), gentamicin (30), kanamycin (30), neomycin (30), novobiocin (30), tetracycline (30), ampicillin (10), erythromycin (15) and rifampicin (5). Cells of strains STR2 T and STR3 T were able to assimilate maltose but only strain STR3 T had N-acetyl-glucosamine assimilation.…”