Antifungal Activity of the Bark Extract of Michelia Alba Against Curvularia Verruculosa Fungal the Cause of Leaf Spot Disease on Rice

The purpose of this study was observe the antifungal activity of the bark extract of Michelia alba against Curvularia verruculosa fungal of the cause of leaf spot disease in rice. The antifungal activities was carried out using the diffusion well, colony, biomass formation methods. The bark extract of Michelia alba has showed the antifungal activity against Curvularia verruculosa fungal with a minimum inhibition concentratiotn value to be 0.5%. The bark extract of Michelia alba with 2.0% concentration can strongly inhibit the growth of C. Verruculosa with inhibiting capabality is 33.17 mm. This extract at 0.6% concentration was able to completely inhibit the growth of fungal colony and at 2.0% concentration has been able to inhibit completely the biomass formation of C. Verruculosa fungal for a 14-day period of incubation.

ANALISIS SENYAWA TERPENOID ANTIJAMUR PADA FRAKSI AKTIF EKSTRAK KULIT KAYU CEMPAKA PUTIH (MICHELIA ALBA) DENGAN METODE GAS CHROMATOGRAPHY-MASS SPECTROSCOPY

The bark extract of Michelia alba was able to inhibit the growth of Curvularia verruculosa fungus which was isolated from leaf spot disease in rice. Separation of the active compound was carried out by column chromatography method using the stationary phase of silica gel and the mobile phase of a mixture of n-hexane-acetone (3: 1). Separation of the active extracts resulted in 10 combined fractions, where 4 fractions showed very strong inhibition, namely the HAE fraction (31.50 mm), HAF (30.13), HAG (48.50), and HAH (34.88). The composition of terpenoid compounds in these fractions was analyzed by Gas Chromatography-Mass Spectrometry. The compound ledenoxid (II) and isoaromadendrene epoxide werefound in almost all of the active fractions, while spathulenol wasfound in the HAF and HAG fractions. Other terpenoid compounds found werecis-farnesol, trans-p-mentha-1 (7), 8-dien-2-ol, and neoclovenoxid-alcohol in the HAE fraction, (-)-caryophyllene oxide and tomentosin in the fraction of HAG. All of the detected terpenoid compounds were compounds from the sesquiterpene group. Keywords: Michelia alba extract, inhibitory power, Curvularia verruculossa, sesquiterpenes

The reaction of lignin model compounds during enzymatic bleaching with a Curvularia verruculosa haloperoxidase: impact on chlorination

Recent developments in enzymatic bleaching processes have led to replacement strategies of harsh chemicals by haloperoxidases. For this purpose, it is important to control the haloperoxidase-mediated formation of adsorbable organic halides (AOX). In this study, we studied the chlorination of monomeric and dimeric lignin model substrates. Guaiacol, acetovanillone, veratryl alcohol, pinoresinol and adlerol were treated with Curvularia verruculosa haloperoxidase and compared to a sodium hypochlorite treatment. High-performance liquid chromatography-diode array detection-mass spectrometry (HPLC-DAD-MS) analysis was employed for the characterization of the reaction products. Our results show that while treatment with haloperoxidases in the presence of sodium chloride and hydrogen peroxide leads to no improvement in AOX formation compared to chemical treatment with NaOCl, addition of ammonium chloride substantially lessens chlorination and promotes β-O-4 ether bond cleavage. The use of ammonium chloride in conjunction with enzymatic haloperoxidase-based bleaching could be a route to minimize lignin chlorination.

Degradation of Petroleum Sludge in Soil by Bacterial-Fungal Co-Culture in Presence of Organic and Inorganic Stimulants

A microcosmic study was carried out for degradation of petroleum sludge [4% (w/w) in soil] in presence of constructed microbial consortium of three bacterial strains i.e., Pseudomonas sp. BP10, Acinetobacter sp. PSM11 and Rhodococcus sp. NJ2 and two fungal strains Panicillium oxalicum PS10 and Curvularia verruculosa PS8, isolated from different petroleum hydrocarbon contaminated sites) supplemented with vermicompost and inorganic fertilizer as biostimulants. After six months of incubation, the maximum degradation of TPH from petroleum sludge was recorded as high as 80% in the presence of combination of inorganic and organic fertilizer and microbial consortium while only 33% degradation was attributed by native organisms and abiotic factors. Enhancement (%) in degradation rate of TPH due to addition of vermicompost, inorganic fertilizer and microbial consortium in separation and combination was recorded as 57%, 13%, 35% and 139%, respectively. Besides the enhancement in specific growth rate of soil microbes due to addition of nutrient, bioaugmentation of this constructed microbial consortium also boost the total bacterial and fungal strains present in petroleum sludge contaminated soil. Catabolic enzymes played an important role in degradation and maximum induction of enzymes likes catechol 1, 2 dioxygenase, catechol 2, 3 dioxygenase, catalase, laccase and dehydrogenase activity were recorded 223.89 μ mol g-1, 323.83 μ mol g-1, 0.714 μ mol H2O2 g-1, 0.623 μ mol g-1 and 3.4 μg g-1 h-1, respectively.