Utilization of used fungus-growing materials of Gastrodia elata / 中国中药杂志

This study aims to explore the resource utilization of used fungus-growing materials produced in the cultivation of Gastrodia elata. To be specific, based on the production practice, this study investigated the recycling mechanism of used fungus-growing materials of G. elata by Phallus inpudicus. To screen edible fungi with wide adaptability, this study examined the allelopathic effects of Armillaria mellea secretions on P. impudicus and 6 kinds of large edible fungi and the activities of enzymes related to degradation of the used fungus-growing materials of G. elata. The results showed that P. impudicus can effectively degrade cellulose, hemicellulose, and lignin in used fungus-growing materials of G. elata. The cellulase activity of A. mellea was significantly higher than that of P. impudicus, and the activities of lignin peroxidase, polyphenol oxidase, and xylanase of P. impudicus were significantly higher than those of A. mellea, which was the important reason why A. mellea and P. impudicus used different parts and components of the used fungus-growing materials to absorb carbon sources and develop ecological niche differences. The growth of P. impudicus was significantly inhibited on the used fungus-growing materials of G. elata. The secretions of A. mellea had allelopathic effects on P. impudicus and other edible fungi, and the allelopathic effects were related to the concentration of allelopathy substances. The screening result showed that the growth and development of L. edodes and A. auricular were not significantly affected by 30% of A. mellea liquid, indicating that they had high resistance to the allelopathy of A. mellea. The results showed that the activities of extracellular lignin peroxidase, polyphenol oxidase, and xylanase of the two edible fungi were similar to those of P. impudicus, and the cellulase activity was higher than that of P. impudicus. This experiment can be further verified by small-scale production tests.

Cloning, expression and characterization of the endoglucanase gene from Bacillus subtilis UMC7 isolated from the gut of the indigenous termite Macrotermes malaccensis in Escherichia coli

Background Bacillus subtilis UMC7 isolated from the gut of termite Macrotermes malaccensis has the ability to secrete a significant amount of extracellular endoglucanase, with an enzyme activity of 0.12 ± 0.01 μmol/min/mL. However, for economically viable industrial applications, the enzyme needs to be expressed in a heterologous host to overcome the low enzyme production from the wild-type strain. Results The endoglucanase gene from B. subtilis UMC7 was successfully cloned and expressed. A higher enzyme activity was observed in the intracellular fraction of the recombinant clone (0.51 ± 0.02 μmol/min/mL) compared with the cell-bound fraction (0.37 ± 0.02 μmol/min/mL) and the extracellular fraction (0.33 ± 0.01 μmol/min/mL). The recombinant endoglucanase was approximately 56 kDa, with optimal enzyme activity at 60°C and pH 6.0. The activity of the enzyme was enhanced by the addition of Ca2 +. However, the enzyme was inhibited by other metal ions in the following order: Fe3 + > Ni2 + > Cu2 + > Mn2 + = Zn2 + > Mg2 + > Cd2 + > Cr2 +. The enzyme was able to hydrolyze both low- and high-viscosity carboxymethyl-cellulose (CMC), avicel, cotton linter, filter paper and avicel but not starch, xylan, chitin, pectin and p-nitrophenyl α-d-glucopyranoside. Conclusions The recombinant endoglucanase showed a threefold increase in extracellular enzyme activity compared with the wild-type strain. This result revealed the potential of endoglucanase expression in E. coli, which can be induced for the overexpression of the enzyme. The enzyme has a broad range of activity with high specificity toward cellulose.

A New Record of Penicillium antarcticum from Marine Environments in Korea

During a survey of marine fungi from the waters surrounding Jeju Island, Korea, several Penicillium strains were isolated from seawater and marine sponges. Based on morphological characteristics and phylogenetic analyses of the internal transcribed spacer and RNA polymerase subunit II, four strains were identified as Penicillium antarcticum, a fungus that, to the best of our knowledge, had not been previously reported in Korea. Here, we provide detailed descriptions of the morphological characteristics and extracellular enzyme activities of the four strains.

Extracellular Enzyme Activities of the Monokaryotic Strains Generated from Basidiospores of Shiitake Mushroom

To obtain basic information on the biochemical property of basidiospores of shiitake mushroom (Lentinula edodes), the ability of producing extracellular enzyme was assessed using a chromogenic plate-based assay. For the aim, amylase, avicelase, beta-glucosidase, CM-cellulase, pectinase, proteinase, and xylanase were tested against monokaryotic strains generated from forty basidiospores of two different parental dikaryotic strains of shiitake mushroom, Sanjo-101Ho and Sanjo-108Ho. These two parental strains showed different degree of extracellular enzyme activity. No identical patterns of the degree of enzyme activity were observed between monokaryotic strains and parental strains of the two shiitake cultivars. The degree of extracellular enzyme activity also varied among monokaryotic strains of the two shiitake cultivars. Our results showed that dikaryotic parental strains of shiitake mushroom produce monokaryotic basidiospores having very diverse biochemical properties.