Utilization of non-pathogenic bacteria to obtain optimum biofilm production for beneficial applications

Abstract

Depending on the bacteria embedded in the extracellular polymeric layer, biofilms can be advantageous or harmful. The isolated strains used in this investigation are already established to be beneficial biofilm-producing bacteria. In order to use them effectively in various domains, it is necessary to characterize them and understand their ideal physiological characteristics for maximum biofilm growth. This study used genome sequence analysis to identify and characterize strains isolated from water samples in Raipur, Chhattisgarh, India. The nucleotide sequences were submitted to NCBI GenBank under the accession numbers Bacillus tequilensis (MN889418) and Pseudomonas beteli (MN889419) and the strains were further characterized using some advanced techniques (phase contrast microscopy, Raman spectroscopy, Fourier-transform infrared spectroscopy, and scanning electron microscope). For maximum biofilm formation by isolated bacterial strains, many physiochemical factors including incubation duration, temperature, pH, carbon source concentration, and nitrogen source concentration were further examined and optimized. The fact that these non-pathogenic strains were found in public water supplies is another important part of this research because there is a chance that they could change into pathogenic state in future and cause disease in humans.

Keywords: Biofilm; Non-pathogenic; Optimization; Physiochemical factors.

Fig. 1

Phylogenetic depicting the relationship between Bacillus tequilensis (MN889418) and Pseudomonas beteli(MN889419) with different reported bacterial strains sequence

Fig. 2

Phase contrast microscopic picture depicting biofilm matrix embedded bacterial isolates (a) for Bacillus tequilensis and (b) for Pseudomonas beteli

Fig. 3

Pictorial representation of surface morphology of biofilm secreted by isolate (a) Bacillus tequilensis and (b) Pseudomonas beteli by scanning electron microscopy

Fig. 4

Biofilm raman spectra for isolate (a) Bacillus tequilensis and (b) Pseudomonas beteli

Fig. 5

FTIR spectrum for biofilm isolated from (a) Bacillus tequilensis and (b) Pseudomonas beteli

Fig. 6

Incubation period optimization result for from Bacillus tequilensis and Pseudomonas beteli (bars represent standard deviation)

Fig. 7

Effect of temperature on biofilm formation from Bacillus tequilensis and Pseudomonas beteli (bars represent standard deviation)

Fig. 8

Effect of pH on biofilm formation by Bacillus tequilensis and Pseudomonas beteli (bars represent standard deviation)

Fig. 9

(a) Influence of different carbon sources on biofilm formation by Bacillus tequilensis and Pseudomonas beteli (bars represent standard deviation). (b): Concentration dependent effect of sucrose on biofilm formation by Bacillus tequilensis and Pseudomonas beteli (bars represent standard deviation)

Fig. 10

(a) Graphical representation of impact of different organic nitrogen sources on biofilm formation efficacy of Bacillus tequilensis and Pseudomonas beteli (bars represent standard deviation). (b): Graphical representations of study on effect of concentration of yeast extract on biofilm formation efficacy of Bacillus tequilensis and Pseudomonas beteli (bars represent standard deviation)