Characterization of biopolymers produced by planktonic and biofilm cells ofHerbaspirillum lusitanumP6‐12

Abstract

Aims: The goal of this study was to characterize biopolymers from two modes of the Herbaspirillum lusitanum P6-12 growth: planktonic, in which cells are free swimming, and biofilm life style, in which the cells are sessile. Methods and Results: Differences in biopolymers composition from planktonic and biofilm cells of H. lusitanum strain P6-12 were analysed using Fourier transform infrared spectroscopy (FTIR), sodium dodecyl sulphate-polyacrylamide gel electrophoresis, gas-liquid chromatography and spectrophotometry. A high degree of polymer separation and purification was achieved by ultracentrifugation, and column chromatography allowed us to identify the chemical differences between biopolymers from biofilm and planktonic H. lusitanum. It was shown that planktonic cells of H. lusitanum P6-12 when cultivated in a liquid medium to the end of the exponential phase of growth, produced two high-molecular-weight glycoconjugates (were arbitrarily called CPS-I and CPS-II) of a lipopolysaccharide (LPS) nature and a lipid-polysacharide complex (were arbitrarily called EPS). The EPS, CPS-I, CPS-II had different monosaccharide and lipid compositions. The extracellular polymeric matrix (EPM) produced by the biofilm cells was mostly proteinaceous, with a small amount of carbohydrates (up to 3%). From the biofilm culture medium, a free extracellular polymeric substance (was arbitrarily called fEPS) was obtained that contained proteins and carbohydrates (up to 7%). The cells outside the biofilm had capsules containing high-molecular-weight glycoconjugate (was arbitrarily called CPS FBC) that consisted of carbohydrates (up to 10%), proteins (up to 16%) and lipids (up to 70%). Conclusions: During biofilm formation, the bacteria secreted surface biopolymers that differed from those of the planktonic cells. The heterogeneity of the polysaccharide containing biopolymers of the H. lusitanum P6-12 surface is probably conditioned by their different functions in plant colonization and formation of an efficient symbiosis, as well as in cell adaptation to existence in plant tissues. Significance and Impact of the Study: The results of the study permit a better understanding of the physiological properties of the biopolymers, for example, in plant-microbe interactions.

Structural characterization and partial properties of dextran produced by Leuconostoc mesenteroides RSG7 from pepino

“…A previous study also indicated the presence of α-(1→6) glycosidic linkage based on the peak of 1,018.96 cm –1 ( Miao et al, 2014 ). The band at 914.56 cm –1 was attributed to the pyranose ring from the glucosyl residue ( Shao et al, 2014 ; Zhou et al, 2018 ) and 838.44 cm –1 was the characteristic of α-Glc ( Zheng et al, 2019 ; Velichko et al, 2020 ), indicating that RSG7 EPS contains typical of α- anomers of Glc. The peaks at the region of 500–800 cm –1 further implied the presence of α-glycosidic linkages ( Naibaho et al, 2022 ).…”

Fourier Transform Infrared (FTIR) Spectroscopic Study of Biofilms Formed by the Rhizobacterium Azospirillum baldaniorum Sp245: Aspects of Methodology and Matrix Composition

“…It has to be noted that the formation of biofilms is a complex, strictly regulated biological process, as a result of which the bacterial community, united by complex intercellular connections, switches to a qualitatively different way of functioning [ 27 , 55 , 56 , 57 , 58 ]. It is known that the process of initiation of biofilm formation and different stages of its development are accompanied by differential expression of bacterial genes [ 56 , 59 ].…”

Engineering biofilm matrix for efficient biofilm-mediated contaminant removal

“…This led to a deformed and weakened biofilm structure and increased sensitivity to anti-tuberculosis drugs. Lipid content is frequently reported to be higher in biofilms than in planktonic cultures [140][141][142]. The common observation in biofilm EPS is the higher abundance of C16-C18 long-chain fatty acids.…”

“…Over 70% of the total fatty acid in EPS isolated from a thermophilic corrosive consortium belonged to the long-chain C16 species [142]. Long-chain fatty acids are speculated to mediate biofilm structure stability through cross-linking with exoproteins and exopolysaccharides during bacterial adaptation to their microenvironment [140],…”