• Korean Journal of Microbiology
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• v.36 no.3
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• pp.228-235
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• 2000

Until now, it was diIliculi to overproduce lignin peroxidase(LiP) fiom Pl~anemchaete ch~ysosporium since the lack of optimized growth conditions. In this paper, we optimized the LIP production conditions and monitored LIP isozyines of fl chqsospoi.ium PSBL-1. The optimized condition includes sponge matrix support, no addition of $MnSO_4$, excess addition of niixogen source(48 inM diarmnonium), and addition of stabilizer(2 mM verakyl alcohol). Finally we obtained Lip activity of 1,800 unitsll. HI isozyne was overproduced when inyceliuin was cultivated in media containing $Mn^{2+}$ (2.73 inM) and excess nitrogen(48 11d4 diannnonium). Three azo dyes(acid yellow 9, congo ued, orange IT; each concenimtion of50 $\mu$M) we1-e rapidly decolorized within 2 inins by 0.4 un~t or Lip.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1467-1475
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• 2015

The use of microbial extracts containing plant hormones is a promising technique to improve crop growth. Little is known about the effect of bacterial cell-free extracts on plant growth promotion. This study, based on phytohormonal analyses, aimed at exploring the potential mechanisms by which Enterococcus faecium LKE12 enhances plant growth in oriental melon. A bacterial strain, LKE12, was isolated from soil, and further identified as E. faecium by 16S rDNA sequencing and phylogenetic analysis. The plant growth-promoting ability of an LKE12 bacterial culture was tested in a gibberellin (GA)-deficient rice dwarf mutant (waito-C) and a normal GA biosynthesis rice cultivar (Hwayongbyeo). E. faecium LKE12 significantly improved the length and biomass of rice shoots in both normal and dwarf cultivars through the secretion of an array of gibberellins (GA₁, GA₃, GA₇, GA₈, GA₉, GA₁₂, GA₁₉, GA₂₀, GA₂₄, and GA₅₃), as well as indole-3-acetic acid (IAA). To the best of our knowledge, this is the first study indicating that E. faecium can produce GAs. Increases in shoot and root lengths, plant fresh weight, and chlorophyll content promoted by E. faecium LKE12 and its cell-free extract inoculated in oriental melon plants revealed a favorable interaction of E. faecium LKE12 with plants. Higher plant growth rates and nutrient contents of magnesium, calcium, sodium, iron, manganese, silicon, zinc, and nitrogen were found in cell-free extract-treated plants than in control plants. The results of the current study suggest that E. faecium LKE12 promotes plant growth by producing GAs and IAA; interestingly, the exogenous application of its cell-free culture extract can be a potential strategy to accelerate plant growth.