Pectin esterase production by Rhizopus stolonifer from post-harvest soft rots of potato tubers in Nigeria and its activity
✍ Scribed by Ogundero, V. W.
- Publisher
- John Wiley and Sons
- Year
- 1988
- Tongue
- English
- Weight
- 330 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0027-769X
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✦ Synopsis
The ahility of R/ti:opu,y .rtu/orr(fer (Ehrrrr e . ~. F r . ) L i d . a common pathogen of post-harvest potato tubcr5 in Nigeria to produce cellwall-degrading cnzymcs was studied. When grown on a basal medium containing 0.5",, (wiv) sodium polypectate at 30 C, only pectin esterase was detected i n the growth medium throughout the incubation period of 10 days. Both exo-and endo-polygalacturonase activity were absent in the growth medium. The pectin esterase was found to be constitutive as it wa$ readily produced on sources o f carbon other than pectin. Partial purification was achieved by a combination of membrane filtration, ethanol precipitation. fractionation on DEAE-cellulosc and gel-filtration on Sephadex G-200. This resulted in a single enzyme peak with a specific activity of 58.5 and a recovery value of4.9",,. The purified enzyme was most activc at pH 8.5 and a temperature of 35 C . It lacked the ability to macerate potato tissue cells and did not induce discolouration of potato discs nor kill the cells. R. s/o/orri/er is discusscd to be probably not strongly pathogenic to post-harvest potato tubers.