NISCAIR Online Periodicals Repository Community: IJBT Vol.10 [2011]

Biodegradation of poultry feathers by a novel bacterial isolate Bacillus altitudinis GVC11

Title: Biodegradation of poultry feathers by a novel bacterial isolate Bacillus altitudinis GVC11

Authors: Kumar, E Vijay; Srijana, M; Chaitanya, K; Reddy, Y Harish Kumar; Reddy, Gopal

Abstract: Keratinolytic microorganisms have great importance in feather waste degradation and its use for improvement of livestock feed and production of protein hydrolysates. Bacillus altitudinis GVC11, a novel, raw chicken feather degrading bacterium, previously isolated and identified by morphological, biochemical and 16s rDNA sequencing in our laboratory, was used in the present study. It was grown in a medium containing only poultry feathers as sole carbon and nitrogen source. GVC11 was able to degrade white and dark chicken feathers in 48 and 96 h, respectively. Degradation of white feather including rachis and barbules was observed under electron microscope. The optimum conditions for keratinase production and feather degradation by GVC11 were pH 9, 37^oC and 200 rpm. Essential amino acids like phenyl alanine, valine, leucine, isoleucine and threonine were observed in supernatant obtained after feather degradation at concentrations of 124, 88, 19, 17, and 11 mols, respectively per 100 mL of broth. Biodegradation of feathers by B. altitudinis GVC11 can be used for keratinase and oligopeptide production and degraded feather biomass can also be utilized as animal feed supplement.

Page(s): 502-507

Pyrene biodegradation by free and immobilized cells of Mycobacterium frederiksbergense using a solvent encapsulated system

Title: Pyrene biodegradation by free and immobilized cells of Mycobacterium frederiksbergense using a solvent encapsulated system

Authors: Sarma, Saurabh Jyoti; Pakshirajan, Kannan; Saamrat, K B G

Abstract: Polycyclic aromatic hydrocarbons (PAHs) are classified as hazardous pollutants in the environment due to their toxic, mutagenic and recalcitrant nature. Compared to other methods, biodegradation using microorganisms seems to be attractive alternative for treating PAH contaminated environment. However, there are limitations because of its low aqueous solubility and negligible bioavailability to the degrading microbes. The present study investigated biodegradation of pyrene, a model PAH compound, using both free and calcium alginate immobilized cells of Mycobacterium frederiksbergense. To overcome the bioavailability problem, organic phase (silicone oil) containing the PAH compound was encapsulated using chitosan coated sodium alginate-polyvinyl alcohol beads for subsequent use in the biodegradation experiments. Prior to the biodegradation experiments, characterization of the silicone oil encapsulated beads and the cell immobilized beads were also performed. In pyrene biodegradation experiments using the free cells, following an initial lag phase of 4 d, ~90% degradation was achieved at 400 and 800 mg/L initial pyrene concentrations. On the other hand, immobilized cells in beads of ~700 m size showed better performance even at a very high initial concentration of 2000 mg/L.

Page(s): 496-501

RAPD profile and rDNA sequence analysis of Talaromyces flavus and Trichoderma species

Title: RAPD profile and rDNA sequence analysis of Talaromyces flavus and Trichoderma species

Authors: Chakraborty, B N; Chakraborty, U; Sunar, K; Dey, P L

Abstract: Talaromyces flavus isolated from paddy rhizosphere exhibited phosphate solubilizing activity in vitro and positively influenced the growth of Oryza sativa, Cicer arietinum and Vigna radiata under green house conditions. Besides, isolates of Trichoderma harzianum and T. asperellum obtained from agricultural field of Darjeeling hills showed antifungal activities against fungal pathogens. Phylogenetic analysis of all these isolates were carried out by sequencing the internal transcribed spacer regions (ITS1 & ITS4) of the ribosomal DNA of T. flavus and T. harzianum using universal primers. The sequences were aligned against ex-type strain sequences from NCBI GenBank. Genetic relatedness among the isolates was studied using random decamer primers. UPGMA cluster analysis showed that the similarity coefficient ranged from 0.37 to 1 for T. flavus and 0.68 to 1 for T. harzianum. The open reading frame (ORF) analysis of 18S rDNA sequence of T. harzianum revealed that the sequence contains in total of four ORFs, encoding 159 amino acids with an estimated molecular mass of 17.84 kDa. The sequences of ITS1 region have been used as the reference sequence, which may be used for future study involving the identification and taxonomy of both T. flavus and Trichoderma isolates.

Page(s): 487-495

Cloning and expression of an intronless gene encoding endoglucanase from Aspergillus fumigatus MKU1

Title: Cloning and expression of an intronless gene encoding endoglucanase from Aspergillus fumigatus MKU1

Authors: Meera, B; Vanitha, M C; Ramani, G; Manjula, A; Gunasekaran, P

Abstract: Endoglucanase (carboxymethyl cellulase) production by an alkali tolerant fungus Aspergillus fumigatus MKU1 was characterized under submerged fermentation conditions. The carboxymethyl cellulase (CMCase) activity was optimal at pH 5.0 and 60°C. Intronless gene eng61 coding for endoglucanase from A. fumigatus MKU1 was cloned and sequenced. The eng61 gene contains 993 bp ORF encoding a polypeptide of 330 amino acids. In silico analysis of the translated sequence revealed the presence of C-terminal cellulose binding module and signal peptide cleavage site between 20^th and 21^st amino acids. The eng61 was cloned in pET30b and expressed in Escherichia coli BL21 DE3. Thus, an intronless endoglucanase gene from an alkali tolerant strain of A. fumigatus has been cloned and expressed.

Page(s): 480-486