Abstract:Diatoms are photosynthetic unicellular microalgae and are nature's hidden source of several biosynthetic metabolites with their use in biofuel, food and drug industries. They mainly contain various lipids, sterols, isoprenoids and toxins with their use in apoptotic, fertility controlling and cancer drugs. Chemical studies on diatoms are limited due to various limitations such as variation of nutrients, contaminants and change in seasonal factors in the environment. To overcome these limitations, we obtained ax… Show more
“…Each peak was assigned a functional group (Table 3). The bands were tentatively identified on the basis of published data for phytoplankton, bacteria, on other biological materials and reference standards (Kumar et al 2018). The peak at 1072 cm -1 corresponds to Si-O bonding ( Table 3).…”
Section: Resultsmentioning
confidence: 99%
“…Diatom species have different types and concentrations of organic contents, and FTIR spectra can give very reliable information about this content. The FTIR study of a bioactive surface such as microorganisms and microalgae reveal the presence of many functional groups on their surfaces (Kumar et al 2018). FTIR spectroscopy is applied in order to detect specific functional groups that help determine the presence of some components (Fig.…”
Section: Discussionmentioning
confidence: 99%
“…1 Band assignment based onKumar et al (2018) growth phases can be recognized(Chaumont 1993, Perumal et al 2012). There are four growth phases for microalgae cultures.…”
This study was performed in order to bring out a detailed information on growth dynamics and biochemical determination of the diatom species Nitzschia palea (Kützing) W. Smith under batch culture conditions in order to pave the way for further studies. The study material was isolated from a fresh water sample collected from Ankara, Turkey. The diatoms were cultured in Allen medium for 168 hours and the growth dynamics were determined by cell density and dry weight analyses. Specific growth rate, duplication time of the culture and biochemical compositions were also investigated. Molecular characterization of the N. palea strain was performed by applying Fourier Transform Infrared Spectroscopy. The cell density and the dry biomass of the culture at the end of the 168 hours incubation period was determined as 2.0x10 6 ±1.0x10 5 cells/mL and 0.212±0.041 g L-1 , respectively. The algal specific growth rate was found as 0.010 h-1 at 96-h and the doubling time was calculated as 68 h-1. The protein content was measured as 41.21%, carbohydrate content as 21.74%, lipid content as 16.84% and ash content as 19.88%. These results indicated that N. palea may be used in different fields of industries, especially in biodiesel production.
“…Each peak was assigned a functional group (Table 3). The bands were tentatively identified on the basis of published data for phytoplankton, bacteria, on other biological materials and reference standards (Kumar et al 2018). The peak at 1072 cm -1 corresponds to Si-O bonding ( Table 3).…”
Section: Resultsmentioning
confidence: 99%
“…Diatom species have different types and concentrations of organic contents, and FTIR spectra can give very reliable information about this content. The FTIR study of a bioactive surface such as microorganisms and microalgae reveal the presence of many functional groups on their surfaces (Kumar et al 2018). FTIR spectroscopy is applied in order to detect specific functional groups that help determine the presence of some components (Fig.…”
Section: Discussionmentioning
confidence: 99%
“…1 Band assignment based onKumar et al (2018) growth phases can be recognized(Chaumont 1993, Perumal et al 2012). There are four growth phases for microalgae cultures.…”
This study was performed in order to bring out a detailed information on growth dynamics and biochemical determination of the diatom species Nitzschia palea (Kützing) W. Smith under batch culture conditions in order to pave the way for further studies. The study material was isolated from a fresh water sample collected from Ankara, Turkey. The diatoms were cultured in Allen medium for 168 hours and the growth dynamics were determined by cell density and dry weight analyses. Specific growth rate, duplication time of the culture and biochemical compositions were also investigated. Molecular characterization of the N. palea strain was performed by applying Fourier Transform Infrared Spectroscopy. The cell density and the dry biomass of the culture at the end of the 168 hours incubation period was determined as 2.0x10 6 ±1.0x10 5 cells/mL and 0.212±0.041 g L-1 , respectively. The algal specific growth rate was found as 0.010 h-1 at 96-h and the doubling time was calculated as 68 h-1. The protein content was measured as 41.21%, carbohydrate content as 21.74%, lipid content as 16.84% and ash content as 19.88%. These results indicated that N. palea may be used in different fields of industries, especially in biodiesel production.
“…However, NS3 contains the least content of C=O stretching (amide I of protein) as it exhibit higher area value as seen in Fig. 1 63 , 64 . Figure 1 Plot of areas under 1800–1100 cm −1 for normalize FT-IR spectra of diatom NS1, NS3, NS4, PB and GP .…”
In the present study, embellishment or beautification of diatoms on substrates like plastics, polydimethylsiloxane, graphite, glass plate, and titanium dioxide, triggered by exopolysaccharides was examined under laboratory conditions. Exopolysaccharides are secreted mainly by primary colonisers, bacteria, which is succeeded by secondary colonisers i.e. diatoms. Both diatom (Nitzschia sp.4) and bacteria (Bacillus subtilis) were exposed with substrates separately for 30 days. Diatoms adhere on substrates strongly, not only because of surface roughness of different substrates but also the nanoporous architecture of diatoms which enhanced their embellishment. This study attempted to identify the substrates that adhere to diatoms strongly and was mainly analyzed by scanning electron microscope and further the observations are well supported by math work software (MATLAB). The variation of diatom’s binding on different substrates is due to the influence of marine litters on diatom population in ocean beds where they undergo slow degradation releasing macro, micro and nanoparticles besides radicals and ions causing cell death. Therefore a proof-of-concept model is developed to successfully deliver a message concerning benefit of using different diatom species.
“…Such composition was already reported for other diatoms. 58 The signature of the amorphous silica from the frustule was not resolved due to weak intensities of their scattering bands. [59][60][61] The spectral fingerprints were very different from individual cells to aggregates.…”
Freshwater biofilms play an essential ecological role, but they also adversely affect human activities through undesirable biofouling of artificial submerged structures. They form complex aggregates of microorganisms that colonize any type of substratum. In phototrophic biofilms, diatoms dominate in biomass and produce copious amount of extracellular polymeric substances (EPSs), making them efficient early colonizers. Therefore, a better understanding of diatoms adhesive properties is essential to develop new anti-biofouling strategies. In this context, we used atomic force microscopy (AFM) to decipher the topography and adhesive mechanisms of the common freshwater diatom Nitzschia palea. Images taken in physiological conditions revealed typical ultrastructural features with a few nanometers resolution. Using single-cell force spectroscopy, we showed that N. palea strongly adheres to hydrophobic surfaces as compared to hydrophilic ones. Chemical force spectroscopy with hydrophobic tips further confirmed that the adhesion is governed by surface-associated hydrophobic EPS distributed in clusters at the frustule surface, and mostly composed of (glyco)-lipids as revealed by Raman spectroscopy. Collectively, our results demonstrate that AFM-based nanoscopy, combined with Raman spectroscopy, is a powerful tool to provide new insights into the adhesion mechanisms of diatoms.
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