الفهرس 
Production and characterization of microbial myrosinaes
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Abstract
Myrosinase hydrolyzes glucosinolates giving various products depending on the
physiological conditions. The hydrolysis products especially isothiocyanates have
antibacterial, antifungal, anticancer activity, act as soil biofumigant, natural pesticides
and food preservatives. Myrosinase is mainly found in cruciferous plants but few
literatures reported its production by both fungi and bacteria. In this study, 94 microbial
isolates from E.sativa and its soil rhizosphere were screened for myrosinase, 25% of
the screened bacterial isolates (9 isolates) and 62.07% of the screened fungal isolates
(36 isolates) had myrosinase activity. About 22.22% of the endophytic bacterial isolates
from E.sativa roots and 63.63% of the endophytic bacterial isolates from E.sativa
leaves were able to produce myrosinase but none of soil rhizosphere and epiphytic
bacterial isolates were able. On the other hand, 72.41% of the E.sativa fungal isolates
of soil rhizosphere, 50% of the endophytic fungal isolates from E.sativa roots, 37.5% of
the endophytic fungal isolates from E.sativa leaves and 63.64% of the epiphytic
isolates had myrosinase activity. This indicated that both endophytic bacterial and
fungal population of E.sativa leaves and roots are good reservoir for myrosinase
activity and the fungal community of the soil rhizosphere and the plant surfaces of
E.sativa seemed to have myrosinase activity rather than the bacteria living there. The
nine myrosinase producing bacterial isolates were phenotypically characterized and
identified based on 16S rRNA sequencing. They all belonged to the genus Bacillus and
they were given the following accession numbers LC589981, LC589982, LC589983,
LC589984, LC589985, LC589986, LC589987, LC589988 and LC589989 on NCBI.
They were all most closely related to Bacillus siamensis and Bacillus velezensis with
identity percent > 99%. The fungal myrosinase producers were identified
morphologically and they belonged to six different genera: Aspergillus, Penicellium,
Fusarium, Eumericella, Alternaria and Sclerotium. Quantitative screening indicated
that Bacillus sp. NGB−B10 was the most reproducible isolate among both the bacterial
and the fungal isolates. Optimizing the culture conditions of Bacillus sp.