Siti Zulaiha Hanapi

A new chitinase-producer strain Streptomyces glauciniger WICC-A03: isolation and identification as a biocontrol agent for plants phytopathogenic fungi

This study discusses the isolation and identification of a new Streptomycetes highly active chitinase producer. Fifteen strains were isolated from Malaysian soil samples. The isolate WICC-A03 was found to be the most active chitinase producer. Its antifungal activity was evaluated against many phytopathogens. The identification of WICC-A03 using phenotypic and genotypic methods strongly indicated that strain WICC-A03 belonged to the genus Streptomyces and displayed similarity (91%) with Streptomyces glauciniger. Thus, it was given the suggested name S. glauciniger WICC-A03 with accession number: JX139754. WICC-A03 produces extracellular chitinase in a medium containing 1.5% colloidal chitin in submerged culture on 144 h. The produced enzyme was partially characterised and its molecular weight of 50 kDa was determined by using SDS-PAGE. This study indicates that WICC-A03 is a potential chitinase producer for biocontrol of plant pathogens. Further experiments are being carried out to optimise medium composition and cultivation conditions under lab and bioreactor scale.

Microbial Effects on Seed Germination in Malaysian rice (Oryza sativa L.)

Seed germination is the basis of plant growth as it determines the viability of rice. A laboratory experiment was conducted to observe the effect of microbial inoculation on seed germination and seedling growth of two lowland rice varieties (Mahsuri and Sri Malaysia 1) and two upland rice landraces (Panderas and SK-1). The experiment was conducted using wet filter paper in Petri dish. The design of the experiment was completely randomized (CRD) with three replicates. Three selected growth promoting microbes Nitrosomonas europaea , Rhodopseudomonas palustris and Acinetobacter sp . were used in the experiment. Seeds inoculated with those microbes and the Petri dish were kept in the dark for five days and subsequently subjected to light condition for another five days. The seed germination and other related attributes were measured. Significance and non significant differences were observed for growth parameters and germination traits, respectively. Among the microbes, Nitrosomonas europaea and its combination performed better in root length and combination of Rhodopseudomonas palustris and Acinetobacter sp . promotes the best growth of shoot. Nitrosomas europaea has shown to play a major role in the germination rate growth in all varieties. It is therefore concluded that growth promoting microbes may have positive effects on germination of rice seeds.

Disease-Suppressive Effect of Compost Tea Against Phytopathogens in Sustaining Herbal Plant Productivity

As for all other important crops, soilborne diseases in herbal plants are becoming a complex and quite prevalent problem that significantly reduced yield production, which may severely influence the bioactive compounds. These valuable crops are taking an increasing relevance in mass, and the dependence on chemical fungicides should be reduced to preserve the qualitative aspect of production. One of the available alternative biological approaches is the compost teas. It is strongly imperative to use it to prevent, suppress, or control wide range of soilborne plant diseases especially caused by fungal phytopathogens. Compost teas are a fermented compost aqueous extract that consists of abundance of antagonistic microbes within it. This review provides the key principles to several aspects of inhibitory potential of compost teas derived from biological origins including fundamental idea for the preparation of compost tea, bio-efficacy effects in managing the plant diseases, as well as mechanism on disease suppression. Better understanding of the antagonism microbial interactions within compost teas will determine the sustainability of any approaches for a biocontrol program. The factors affecting their effectiveness also will be briefly explained. Finally, future research is proposed to further validate the strategies of compost teas as suitable tool of plant protectants toward an improvement of the overall health of plants.

Antioxidant Compounds of the Edible Mushroom Pleurotus ostreatus

Mushrooms have been used since centuries in many ancient cultures as source of food and medicine. However, until now the therapeutic values of mushrooms position this group of macrofungi as one of the major component in traditional medicine practice especially in South East Asia and China. Of different species of known mushrooms, Pleurotus spp. is widely known as part of food chain based on its high nutritional value. However, of the more than 70 species known, only few species are cultivated in mass production and used such as P. ostreatus, P. florida, and P. ajor-caju. However, P. ostreatus (widely known as oyster mushroom) received more attention in food industries based on its high growth rate and ease of cultivation using different substrates. This mushroom is rich of wide range of bioactive molecules of proven medicinal values with many therapeutic activities as anticancer, immunomodulatory, antiapoptotic, anti hypocholesterolemic, anti hyperglycemic, antimicrobial, anti-inflammatory, anti-osteoporetic, and many others. This work focuses on reviewing on the different classes of oyster mushroom bioactive compounds of antioxidant activities such as phenolics, beta carotene, lycopene, ascorbic acid, tocopherols, and ergosterols. This review provides also comprehensive information on the recent research to enhance the antioxidant properties through alteration of the cultivation strategy and addition of some compounds during the cultivation of P. ostreatus.

Mycoremediation: Decolourization Potential of Fungal Ligninolytic Enzymes

Textile industry is the most avid user for dyes. Rapidly growing interest in developing more synthetic commercial dyes from its native to endeavour human needs contributed to aesthetic problems to the environment and public health. Increasing concerns about colours in the effluents lead to worldwide efforts to develop more effective colour removal processes. However, the physical and chemical treatment methods of the discharge effluents are not economically feasible even if some of them are inefficient nowadays. Furthermore, liberating the hazardous product from secondary pollution from these methods acquires valid waste management system. Without proper discharge, azo dyes and associated chemicals may induce mutagenesis leading to toxicity in aquatic plants and animals. Utilization of mycoremediation of dyes as green chemistry technology has yet become a promising approach due to its clear picture of cost, eco-friendly and environmentally benign process as an alternative green solution to replace or supplement for current and future environmental issues. The bioremediation using fungi was reported to be more tolerant than bacteria and more efficient for decolorization as well as degradation of toxic chemicals. However, white-rot fungi are well known for their outstanding ability in bioremediation process. Their ability to produce highly non-specific extracellular enzymes allows them to degrade a wide array of pollutants resembling dyes and its derivatives. White-rot fungi secrete one or more of the three principle ligninolytic enzymes: lignin peroxidase (LiP, E.C. 1.11.1.14), Mn-dependent peroxidase (MnP, E.C. 1.11.1.13) and phenol oxidase (laccase) (Lac, E.C. 1.10.3.2) and other peroxidases. The present review discusses comprehensively the science and technology of biodegradation and fungal bioremediation of synthetic dyes.

The Edible Mushroom Pleurotus spp.: II. Medicinal Values

Mushrooms health benefit was recognized in the Orient from several thousand years ago as globally consumption and has third largest commercially production. The genus Pleurotus (oyster mushroom) is an organoleptic fast growing fungus which belongs to basidiomycota group. Although 70 species is discovered until now for this genus, but only few of them are available in market such as Pleurotus florida, P. sajor-caju and P. ostreatus. They have been used in human diet throughout the world due to their rich nutrients such as protein, fiber carbohydrate, minerals, vitamins and lipid. It should be noted that low amount calories, Sodium, fat and cholesterol is reported in this genus. Many pharmaceutical companies in the Far East and China are viewing the medicinal mushrooms as a rich source of innovative biomedical molecules. These molecules can be extracted from different part of oyster mushroom such as fruiting body, mycelia and culture broth. Mainly they are biopolymers including polysaccharides, proteins and nucleic acids as they are more variable to carry biological information. The medicinal properties of Pleurotus spp studied by several authors, as a result antitumor, immunomodulating, antiviral, antibacterial, antigenotoxic, antioxidant, anti-inflammatory, hypocholesterolamic, antihypertensive, antiinociceptive, anti-hyperglycaemic, anti-platelet-aggregating, antihepatoma, anti poliferative and antiatherosclerotic. In this chapter, biodivertsity of genus Pleurotus will be discussed regarding nutritional and bioactive compounds. Furthermore the prospective of oyster mushroom for therapeutic application and concept will be highlighted.

Effect of additives on Pleurotus ostreatus Growth on Agar medium

Oyster mushroom (Pleurotus ostreatus) is one of the most widely grown mushrooms worldwide. This type of fungus have been grown for centuries in green houses to produce mycelium and fruiting bodies and marketed as highly nutritious food. Like many other mushrooms, oyster mushroom characterized by lower growth rate which consume long time on agar medium for inoculum preparation for spawn preparation. Therefore, design of new cultivation medium to shorten the cultivation time on solid medium is necessary to reduce time and produce inoculum with less cost. This work was focused on optimization of agar medium (using the conventional potato dextrose agar medium PDA as base medium for growth and supplemented with other components such as malt extract, yeast extract, and sodium nitrates). The results clearly demonstrate that addition of malt extract and yeast extract support dense cell growth but not fast radial growth on agar medium. Addition of sodium nitrate in addition to malt and yeast extract, increase both of radial cell growth and dense growth as well. Therefore, for fast growth of Pleurotus ostreatus on agar medium its recommended to supplement the growth medium with malt extract, yeast extract, and sodium nitrate.