Mycobiota variation in stored rice straw and its cellulolytic profile

Crude Citric Acid of Trichoderma asperellum: Tomato Growth Promotor and Suppressor of Fusarium oxysporum f. sp. lycopersici

Presently, the bioprocessing of agricultural residues to various bioactive compounds is of great concern, with the potential to be used as plant growth promoters and as a reductive of various diseases. Lycopersiconesculentum, one of the most consumed crops in the human diet, is attacked by Fusarium wilt disease, so the main aim is to biocontrol the pathogen. Several fungal species were isolated from decayed maize stover (MS). Trichodermaasperellum was chosen based on its organic acid productivity and was molecularly identified (GenBank accession number is MW195019). Citric acid (CA) was the major detected organic acid by HPLC. In vitro, CA of T.asperellum at 75% completely repressed the growth of Fusariumoxysporum f. sp. lycopersici (FOL). In vivo, soaking tomato seeds in CA enhanced the seed germination and vigor index. T. asperellum and/or its CA suppressed the wilt disease caused by FOL compared to control. There was a proportional increment of plant growth and yield, as well as improvements in the biochemical parameters (chlorophyll pigments, total phenolic contents and peroxidase, and polyphenol oxidase activities), suggesting targeting both the bioconversion of MS into CA and biological control of FOL.

Secondary metabolites from Penicillium sp. 8PKH isolated from deteriorated rice straws

In the search for bioactive secondary metabolites from terrestrial fungi, four compounds, namely, 3-methyl-3H-quinazolin-4-one (1), aurantiomide C (2), 3-O-methylviridicatin (3), and dehydrocyclopeptine (4), were isolated from Penicillium sp. 8PKH, fungal strain, isolated from deteriorated rice straws. The structures of the isolated compounds were identified by extensive NMR and mass analyses and comparison with literature data. This is the first report of the structure of 3-methyl-3H-quinazolin-4-one (1) with full NMR spectral data having been previously identified by GC-MS from Piper beetle. Analysis of the non-polar fractions of the strain extract by GC-MS revealed the presence of additional eight compounds: methyl-hexadecanoate, methyl linoleate, methyl-9 (Z)-octadecenoate, methyl-octadecanoate, cis-9-oxabicyclo (6.1.0) nonane, 9,12-octadecadienal (9E,12E), ethyl-(E)-9-octadecenoate, and 3-buten-2-ol. The isolated compounds were evaluated for their antimicrobial and cytotoxic activities and exhibited little or no inhibitory activities against the test strains. The taxonomical characterisation and fermentation of the fungal strain were reported as well.