ROLE OF EXTRACELLULAR LIGNOLYTIC ENZYMES IN SUBSTRATE DEGRADATION AND FRUITING INITIATION BY DIFFERENT STRAINS OF Lentinula edodes
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Date
2019
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Indira Gandhi Krishi Vishwavidyalaya, Raipur
Abstract
Shiitake Lentinula edodes (Berk.) Pegler is the most cultivating mushroom in the world contributing 22% of overall global mushroom production. Derived its name due to association with Japanese “Shii tree” (Castnopsis cuspidate Schotty) has been highly rated delicacy in South East Asia because of its exotic taste, flavor, enciting aroma, and mineral availability. Besides its culinary important was used for medicinal properties like anticancer, antidiabetic, immunomodulting, antithrombotic, antibacterial and antifungal. Traditional cultivation was based on hardwood logs taken long time for production and lower yield cause sifted towards supplemented synthetic saw dust log bag cultivation. Rather significant performance on different substrate yield and quality, there was very little knowledge towards the active participation of lignolytic enzymes in deconstruction of substrate. Due to the producers of an array of hydrolytic and oxidative enzyme for bioconversion related mainly with growth on substrate.
To understand the physiological mechanisms by regulating enzyme in bioconversion of substrate into mushroom morphogenesis, and substrate degradation to predict fruiting cycles. The present investigation was under taken for “Role of extracellular lignolytic enzymes in substrate degradation and fruiting initiation by different strains of Lentinula edodes”. In the view to explore the role of different ligninolytic enzymes secreted by 19 different strains of Lentinula edodes species were procured form culture bank of ICAR-DMR institute. To know the role of substrate degradation, and fruiting initiation, which secreted during growth and development on synthetic saw-dust bag of locally available Tunni (Toona ciliata) tree was used. The present study was conducted on ICAR-DMR institute with two separated work earlier one on shiitake cultivation practices done partially on laboratory up to spawn formation, and inoculation of synthetic bags thereafter on cultivation room, and the later one in culture laboratory at constant abiotic factors.
The six main extracellular ligninolytic enzymes was studied are (Laccase. MnP, LiP, FPase, CMCase, Xylanase) on every seven days of interval after inoculation (7 DAI, 14 DAI, 21 DAI, 28 DAI, 35 DAI, and 42 DAI), in two separate days of group first three days for substrate degradation, and later three days for fruiting initiation. The release of laccase was significantly maximum in 7 DAI in strain DMRO-35 and found minimum with 42 DAI on DMRO-35 strains, shown the highest concentrations of released enzymes on earlier days than proceeding days of colonization, correlated highly positive with yield shows there was significant role in degradation of the substrate. MnP assay also revealed that the highest concentration released on prior days after inoculation and decrease thereafter, shown significantly maximum in strains DMRO-34, DMRO-329, DMRO-297, DMRO-329, DMRO-330, and DMRO-623 on 7, 14, 21, 28, 35, and 42 DAI respectively, correlated highly significant with yield on 14, and 21 DAI, and formation of bumps on different fruit body 14DAI. There was fluctuating in release of LiP enzyme concentrations on growth and development of mycelium shown maximum in DMRO-22, DMRO-35, DMRO-331, and DMRO-328 on 14, 21, 35, and 42 DAI, all the oxidative enzyme assayed in international unit IU/ml. For hydrolytic enzymes the initial concentration was limited and shown highest peak at the maturation of mycelium causing initiation of pin head initiation and growth of developing fruiting body. Enzyme FPase increased gradually from 7 DAI to 42 DAI with maximum for strain DMRO-20. CMCase enzyme highest for strain DMRO-412 at 21 DAI, correlated highly significant at 35 DAI with yield, and significant negative with number of days required for bumps formation on bags. Xylanase was also increased to its maximum on later days of mycelial maturation with maximum in DMRO-51.
The number of days required form inoculation to fruiting was obtained significantly highest in DMRO-388(s) was of 79 days, with maximum Biological efficiency (202.7 gm). The lowest moisture weight and maximum dry weight was found maximum significantly for strain DMRO-328 with highest accumulation of polyphenols (ash weight). The characteristic of standard fruit body morphologically significant with maximum in pileus length for DMRO-331, pileus diameter for DMRO-20, stipe length and stipe diameter both for DMRO-331. The pH of the substrate was decrease gradually from neutral to acidic in colonizing fungi to bumps formation on bags with significantly for strains DMRO-388(s) (5.0-3.5 pH) from rapidly after inoculation.
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