Gas chromatography/mass spectrometry as a suitable alternative technique to evaluate the ability of Streptomyces to degrade lignin from lignocellulosic residues

Abstract

Low molecular weight aromatic compounds released during the growth of several Streptomyces strains on wheat straw in solid-state fermentation (SSF) were identified by gas chromatography/mass spectrometry. The analysis of the compounds derived from p-hydroxyphenyl, guaiacyl and syringyl units (H, G and S respectively) of lignin indicate the ability of streptomycetes to depolymerize lignin from lignocellulose substrates. Differences in the relative area of the compounds obtained from fermented substrate from the uninoculated control were observed. Moreover, the different proportion of the aromatic compounds obtained from fermented wheat straw proved that the ability to depolymerize lignin in Streptomyces is strain specific. The predominance of acidic forms among these compounds showed an oxidative attack on lignin by Streptomyces. The high level of vanillic acid released from lignin by the strains Streptomyces UAH 23 and Streptomyces UAH 33 seems to indicate the breakdown of Ca-Cb linkages in the lignin molecule. The biotechnological applications of ferulic and vanillic acid as precursors of food additives is also undertaken.

Laccase from prokaryotes: a new source for an old enzyme

“…This result also confirmed the potential application of the laccases from Streptomycetes in biobleaching of kraft pulps in the presence of a synthetic mediator (Arias et al 2003). The detection of low-molecular-weight aromatic compounds, such as p-hydroxybenzoic acid, after growth of Streptomycetes on wheat straw (Hernández-Coronado et al 1998) could open new possibilities for the use of natural mediators together with bacterial laccases for biobleaching. In fact, p-hydroxybenzoic acid has been considered a mediator as efficient as ABTS for the oxidation of polycyclic aromatic hydrocarbons (Johannes and Majcherczyk 2000).…”

Isolation and characterization of bacterial strains Paenibacillus sp. and Bacillus sp. for kraft lignin decolorization from pulp paper mill waste

“…GC-MS analysis revealed the formation of low molecular weight compounds released from KL due to its degradation (Hernandez-Coronado et al, 1998;Ksibi et al, 2003). The Total Ion Chromatograph (TIC) corresponds to the ethyl acetate-extractable compounds from acidifi ed supernatants obtained from the control and degraded sample by strains ITRC S 6 and ITRC S 8 as shown in Fig.…”

“…Apart from phenolics monomers, there are many acidic compounds identifi ed, which are identical to those in the control sample. The guaiacol released by the action of strain ITRC S 6 on KL has great industrial value in the preservative industry due to it ability to inhibit peroxidation of fatty acid (Hernandez-Coronado et al, 1998). …”

Kraft Pulp Biobleaching and Mediated Oxidation of a Nonphenolic Substrate by Laccase from Streptomyces cyaneus CECT 3335

“…Because the use of ABTS as a mediator for biobleaching of pulps is not considered cost-effective at an industrial scale, the search for natural mediators is a current research priority. The detection of low-molecular-weight aromatic compounds, such as p-hydroxybenzoic acid, after growth of streptomycetes on wheat straw (21) could open new possibilities for the use of natural mediators together with bacterial laccases for biobleaching. In fact, p-hydroxybenzoic acid has been considered a mediator as efficient as ABTS for the oxidation of polycyclic aromatic hydrocarbons (24).…”