Molecular weight and ionic strength dependence of fluorescence intensity of the Calcofluor/β-glucan complex in flow-injection analysis

Kim, Sang-Hoon; Inglett, George E.

doi:10.1016/j.jfca.2005.11.006

Cited by 20 publications

(7 citation statements)

References 15 publications

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“…Calcofluor White reagent (Polysciences Inc., Warrington, PA, USA) is a fluorochrome that specifically binds to fibrillar β-glucans (Wood and Weisz 1984). It is widely used to quantify β-glucans by flow-injection analysis (Kim and Inglett 2006). Here, random samples of the dried algae cellulose cake were treated with freshly made Calcofluor White solution (0.01% in 0.1 M K 2 HPO 4 ) and examined using bright-field and fluorescence microscopy (Zeiss Axioplan; exciter filter 365, chromatic beam splitter FT 395, barrier filter LP420).…”

Section: Methodsmentioning

confidence: 99%

Bacterial production of free fatty acids from freshwater macroalgal cellulose

Hoover

Marner

Brownson

et al. 2011

Appl Microbiol Biotechnol

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The predominant strategy for using algae to produce biofuels relies on the overproduction of lipids in microalgae with subsequent conversion to biodiesel (methyl-esters) or green diesel (alkanes). Conditions that both optimize algal growth and lipid accumulation rarely overlap, and differences in growth rates can lead to wild species outcompeting the desired lipid-rich strains. Here, we demonstrate an alternative strategy in which cellulose contained in the cell walls of multicellular algae is used as a feedstock for cultivating biofuel-producing micro-organisms. Cellulose was extracted from an environmental sample of Cladophora glomerata-dominated periphyton that was collected from Lake Mendota, WI, USA. The resulting cellulose cake was hydrolyzed by commercial enzymes to release fermentable glucose. The hydrolysis mixture was used to formulate an undefined medium that was able to support the growth, without supplementation, of a free fatty acid (FFA)-overproducing strain of Escherichia coli (Lennen et. al 2010). To maximize free fatty acid production from glucose, an isopropyl β-D-1-thiogalactopyranoside (IPTG)-inducible vector was constructed to express the Umbellularia californica acyl–acyl carrier protein (ACP) thioesterase. Thioesterase expression was optimized by inducing cultures with 50 μM IPTG. Cell density and FFA titers from cultures grown on algae-based media reached 50% of those (~90 μg/mL FFA) cultures grown on rich Luria–Bertani broth supplemented with 0.2% glucose. In comparison, cultures grown in two media based on AFEX-pretreated corn stover generated tenfold less FFA than cultures grown in algae-based media. This study demonstrates that macroalgal cellulose is a potential carbon source for the production of biofuels or other microbially synthesized compounds.

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Section: Methodsmentioning

confidence: 99%

Bacterial production of free fatty acids from freshwater macroalgal cellulose

Hoover

Marner

Brownson

et al. 2011

Appl Microbiol Biotechnol

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“…The purpose of this study is to explore the interactions between Calcofluor and oat β-glucan molecules. Previous papers have suggested that the binding between Calcofluor and β-glucan is dependent on the ionic strength of the solution and molecular weight of β-glucan (15). Temperature, ethanol, and maltose were mentioned to be factors that interfered with the combination of Calcofluor with β-glucan (12).…”

Section: Introductionmentioning

confidence: 99%

Interactions between Oat β-Glucan and Calcofluor Characterized by Spectroscopic Method

Wu¹,

Xiao²,

Tian³

et al. 2008

J. Agric. Food Chem.

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This paper describes the binding of Calcofluor, a fluorescent probe, to oat beta-glucan in buffer solutions. The binding equilibrium constant (K), the total number of binding sites per beta-glucan molecule (N), and the average binding number of Calcofluor per beta-glucan molecule (n) were determined by UV spectroscopic method. The results indicate that the association of Calcofluor and beta-glucan is driven by both enthalpy and entropy and that the process involves hydrogen bonding, van der Waals forces, and hydrophobic interaction. Higher buffer concentration and NaCl facilitate the binding of Calcofluor to beta-glucan. The adsorption isotherm fits a Langmuir model quite well.

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“…in the presence of a large excess of Na + , Mg 2+ and Ca 2+ ions (50 mM); presumably resulting from the higher ionic strength. 15 With the employed concentration of the probe (10 mM), i.e. a concentration at which the ligand still has sufficient emission intensity, the limit of detection of Hg 2+ ions is 10 À6 M, and the linear range of the detection is 20-90 mM (20-70 mM at higher ionic strength).…”

mentioning

confidence: 99%