Effect of the Composition of Culture Media on the Laccase Production ofLentinus edodes Strains

Abstract

The effect of charge, ion radii and concentration of cations and fermentation time on the laccase production of four Lentinus edodes strains was determined using 28 different fermentation media and 60 days of fermentation time. Samples were taken every 10 days and the laccase activity was determined by visible spectrophotometry. Principal component analysis (PCA) was used for the assessment of similarities and dissimilarities between the laccase activities of the samples. As PCA is not suitable for the separation of the strength (potency) and selectivity of the effect of various factors (composition of cultures, fermentation time, Lentinus edodes strains) on the laccase production, they were separated by the spectral mapping technique (SPM). The dimensionality of the matrices of PC loadings and variables and the selectivity maps were reduced to two by the non-linear mapping technique. The results of PCA and SPM were compared by calculating linear relationships among the potency values and the corresponding coordinates of PCA and SPM maps. It was established that neither the type of the cations nor their concentration in the fermentation media had a significant effect on the laccase production. It was found that the type of the Lentinus edodes strains and the fermentation time exerts a considerable effect both on the strength and on the selectivity of the laccase production. It was further proven that the results of PCA and SPM were considerably different. Therefore, their simultaneous application in future quantitative structure activity relationship (QSAR) studies is highly recommended.

Degradation of eucalypt waste components by Lentinula edodes strains detected by chemical and near-infrared spectroscopy methods

“…Spectral data were analyzed in digitized form at 2 nm intervals from 1000 to 2500 nm. All spectra were converted to secondderivative (inverted peaks) by a Kubelka-Munk transformation and a standardized normalization procedure by using the SPECTRUM R software (13,14). Utilizing the Kubelka-Munk theory, the reflectance (R) can be related to the absorption coefficient (K) and scattering coefficient (S) by the following equation (14): Standardized normalization procedure was applied in order to remove any systematic variation, reducing the effect of a baseline drift in the original NIR spectra.…”

“…Almost all the strains used in this work showed selective lignin removal over biodegradation periods no longer than 2 mo. Usually, signifficant differences in lignin removal can be visualized only if substrate is extensively degraded (4,14). Table 1 shows the correlation factors obtained for carbohydrate and lignin between the control and the biodegraded samples.…”