Chromatographic analysis of lignans.

Methods and procedures for analysis of lignans in trees and other plants are reviewed. The importance of cautious sample handling and pretreatment procedures to avoid contamination, loss of sample, and unwanted chemical reactions is discussed. Sequential extraction with a non-polar solvent followed by extraction with acetone or ethanol is recommended to separate the lignans from the plant matrix. An additional step of acid, alkaline, or enzymatic hydrolysis may be necessary for some plant matrixes. Flash chromatography is a convenient method for preparative separation and isolation of pure lignans from raw extracts. TLC is very suitable for qualitative screening of extracts and for monitoring of lignan isolation and purification steps. Trimethylsilyl ethers of lignans can be separated and quantified by GC even in the case of complex mixtures of lignans and other polyphenols, and the lignans can be identified by GC-MS in a routine manner. HPLC on reversed-phase columns is especially suited for analysis of lignans and their metabolites in biological matrixes. The recent development of HPLC-electrospray ionisation (ESI)-iontrap MS (MS(n)) and corresponding techniques with high sensitivity and selectivity has proven valuable in lignan analysis. Lignan enantiomers can be separated on chiral HPLC columns.

Antibacterial effects of knotwood extractives on paper mill bacteria.

Hydrophilic knotwood extracts from 18 wood species were assessed in disc diffusion and liquid culture tests for antibacterial effects against three species of paper mill bacteria. The Pinus sylvestris, P. resinosa, P. contorta, and P. banksiana extracts decreased or inhibited bacterial growth. The susceptibility order was P. sylvestris > P. resinosa > P. contorta > P. banksiana, correlating with the concentrations of pinosylvin and pinosylvin monomethyl ether in these wood species. Also, Pseudotsuga menziesii and Thuja occidentalis extracts had a small inhibitory effect. The Gram-positive Bacillus coagulans was more susceptible to the extracts than the Gram-negative Burkholderia multivorans and Alcaligenes xylosoxydans. The main components in the Pinus knotwood extracts were pinosylvin monomethyl ether and pinosylvin, suggesting these to be the active components. Therefore, pure pinosylvin, pinosylvin monomethyl ether, and dihydro-pinosylvin monomethyl ether were also tested. All compounds showed antibacterial effects. However, higher concentrations were needed for these pure compounds than for the knotwood extracts. Pinosylvin had stronger antibacterial effects than pinosylvin monomethyl ether. This work shows that knotwood extracts, especially from Pinus species, have a potential for use as natural biocides in papermaking.

Sugar composition of biofilms produced by paper mill bacteria.

Biofilms of paper mill bacteria were cultivated in paper mill white water-simulating conditions on glass slides or stainless steel coupons in a laboratory culture system. The sugar content and composition of the biofilms were analysed and compared with the sugar composition of paper mill slimes. Acid methanolysis followed by gas chromatography revealed that Burkholderia was the major biofilm producer in pure culture, producing up to 50 microg of biofilm sugar cm(-2) in 5 days in rich medium and 10 microg in paper mill simulating medium. A mixture of simulated paper mill water with a culture medium yielded more biofilm (100 microg cm(-2)) than either of the media alone, so the biofilm accumulation was not proportional to the available substrate. More biofilm accumulated on stainless steel coupons than on glass slides, and the steel-coupon biofilms contained slightly more uronic acids. The biofilm sugars contained mainly galactose, glucose, mannose, and rhamnose. In paper mill medium, the Burkholderia biofilm contained more galactose and glucose, and less rhamnose, than in rich laboratory medium. The sugar composition of paper mill slimes was quite similar to those of steel-cultured Burkholderia cepacia biofilms. This suggests that Burkholderia cepacia is responsible for much of the slime in the paper mill.

Degradation of paper mill water components in laboratory tests with pure cultures of bacteria.

The degradation of dissolved and colloidal substances from thermomechanical pulp (TMP) by bacteria isolated from a paper mill was studied in a laboratory slide culture system. Burkholderia cepacia strains hydrolysed triglycerides to free fatty acids, and the liberated unsaturated fatty acids were then degraded to some extent. Saturated fatty acids were not notably degraded. However, the branched anteiso-heptadecanoic fatty acid was degraded almost like the unsaturated fatty acids. About 30% of the steryl esters were degraded during 11 days, increasing the concentrations of free sterols. Approximately 25% of the dehydroabietic, and 45% of the abietic and isopimaric resin acids were degraded during 11 days. The degree of unsaturation seemed to be of greater importance for the degradation of fatty acids than the molar mass. No degradation of dissolved hemicelluloses could be observed with any of the nine bacterial strains studied. Burkholderia cepacia strains and one Bacillus coagulans strain degraded monomeric fructose and glucose in winter TMP water, but in summer TMP water, with much lower sugar concentrations, also other Bacillus strains degraded monomeric sugars.