Isolation and Identification of Antibacterial Bioactive Compounds From Bacillus megaterium L2

Abstract

Bacterial metabolites exhibit a variety of biologically active compounds including antibacterial and antifungal activities. It is well known that Bacillus is considered to be a promising source of bioactive secondary metabolites. Most plant pathogens have an incredible ability to mutate and acquire resistance, causing major economic losses in the agricultural field. Therefore, it is necessary to use the natural antibacterial compounds in microbes to control plant pathogens. This study was conducted to investigate the bio-active compounds of Bacillus megaterium L2. According to the activity guidance of Agrobacterium tumefaciens T-37, Erwinia carotovora EC-1 and Ralstonia solanacearum RS-2, five monomeric compounds, including erucamide (1), behenic acid (2), palmitic acid (3), phenylacetic acid (4), and β-sitosterol (5), were fractionated and purified from the crude ethyl acetate extract of B. megaterium. To our knowledge, all compounds were isolated from the bacterium for the first time. To understand the antimicrobial activity of these compounds, and their minimum inhibitory concentrations (MICs) (range: 0.98∼500 μg/mL) were determined by the broth microdilution method. For the three tested pathogens, palmitic acid exhibited almost no antibacterial activity (>500 μg/mL), while erucamide had moderate antibacterial activity (MIC = 500 μg/mL). Behenic acid showed MICs of 250 μg/mL against T-37 and RS-2 strains with an antibacterial activity. β-sitosterol showed significant antimicrobial activity against RS-2. β-sitosterol showed remarkable antimicrobial activity against RS-2 with an MIC of 15.6 μg/mL. In addition, with the antimicrobial activity, against T-37 (62.5 μg/mL) and against EC-1 (125 μg/mL) and RS-2 (15.6 μg/mL) strains notably, phenylacetic acid may be interesting for the prevention and control of phytopathogenic bacteria. Our findings suggest that isolated compounds such as behenic acid, β-sitosterol, and phenylacetic acid may be promising candidates for natural antimicrobial agents.

Investigation of bioactive compounds from Bacillus sp. against protein homologs CDC42 of Colletotrichum gloeosporioides causing anthracnose disease in cassava by using molecular docking and dynamics studies

“…The molecular docking results for active compounds identified from B. megaterium were shown in Table 1. Inconsistent with previous reports from Xie et al (2021), the results from the present study also showed β-sitosterol and phenylacetic acid as the top hits in molecular docking. Through binding site prediction, it was observed that Leu158, Ser121, Thr117, Glu118, Ser88, Thr87, Ala15, Glu18, and Gly14 are the active residues of CDC42.…”

“…Diclofenac is used as a medication for the treatment of pain and inflammation (Gan 2010). Apart, the previous report indicated that the purified components possess significant antimicrobial activity against plant pathogens such as A. tumefaciens (T-37), Erwinia carotovora (EC-1), and Ralstonia solanacearum (RS-2) (Xie et al, 2021). Among the five components investigated against plant pathogens, β-sitosterol, behenic acid, and phenylacetic acid displayed significant antimicrobial activity.…”

Bio-priming with a consortium of Streptomyces araujoniae strains modulates defense response in chickpea against Fusarium wilt

“…Similarly, the TN19 strain had predominantly valinomycin (3.89%), dinactin (1.56%), and 4-aminobenzoic acid (1.31%). Earlier Qi et al (2022) and Xie et al (2021) , reported antifungal properties of Erucamide. Antifungal properties of dinactin have been reported against various fungi like Pestolotiopsis mangiferae , Neoscytalidium dimidiatum , Fusarium dimerum , Magnaporthe oryzae , Alternaria solani , Fusarium oxysporum f.sp.…”

Isolation of Bioactive Compounds, Antibacterial Activity, and Action Mechanism of Spore Powder From Aspergillus niger xj

“…Determination of antimicrobial properties of (bio)molecules has been conventionally performed using minimum inhibitory concentration (MIC) ( Dudu et al, 2021 ). The MIC values were defined as the lowest concentration at which there is no visible turbidity ( Mawire et al, 2021 ), and the MIC was determined by broth microdilution assay as described by Xie et al (2021) with some modifications. T-37, EC-1, and RS-2 strains were incubated at 30°C for logarithmic phase to approximately 10 8 CFU/ml in beef extract peptone liquid medium previously.…”