Biodegradation of cotton straw byPleutorus florida |
| |
Authors: | M W Platt Y Hadar A Hisdai I Chet |
| |
Institution: | (1) Department of Plant Pathology and Microbiology, Hebrew University, Israel;(2) Department of Animal Metabolism, Volcani Institute, Israel |
| |
Abstract: | Cotton straw is an unutilized waste product containing 25% lignin, thus making it unsuitable for use as animal feed.
This material was found to be an excellent substrate for the growth of the edible mushroomPleurotus florida. A growth-promoting flavonoid was isolated from the water-soluble fraction of the straw (Platt et al., 1983).
After 3 wk of fungal growth on native cotton straw, an 18% decrease in dry weight occurred. Lignin (insoluble in 72% H2SO4) was degraded from the 8th d of growth up to a total of 65% of the original content after 21 d. Prior to lignin degradation,
sugars and other water-soluble materials were removed and laccase activity (substrate, 2,6-dimethoxyphenol) was detected.
This activity disappeared after the eighth day of growth. In all our experiments it appears that laccase activity precedes
the onset of lignin degradation. Cellulase activity reached a maximum after 8 d of fungal growth and immediately disappeared.
Total fungal activity was estimated by measuring hydrolysis of fluorescein diacetate (FDA), which indicated a gradual increase
during the first 8 d and then reached a plateau. Release of glucose from the straw by commercial cellulase increased with
duration of fungal growth from 28 (Μ/g/h-1 to 250 Μg/g/h-1. These results are corroborated by information from artificial rumen experiments showing an increase of in vitro dry matter
digestability from 26 to 38%. In comparison, on washed straw, FDA and laccase activity was three-fold smaller. Final dry weight
reduction was 10.1%, while total lignin loss was only 33% of the original lignin content. It seems that the water-soluble
materials are responsible for the rapid growth, increased enzymatic activity, and total degradation of cotton straw byP. florida. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|