Enhanced cellulase producing mutants developed from heterokaryotic Aspergillus strain.
A heterokaryon 28, derived through protoplast fusion between Aspergillus nidulans and Aspergillus tubingensis (Dal8), was subjected cyclic mutagenesis followed by selection on increasing levels of 2-deoxy glucose (2-DG) as selection marker. The derived deregulated cellulase hyper producing mutant '64', when compared to fusant 28, produced 9.83, 7.8, 3.2, 4.2 and 19.74 folds higher endoglucanase, β-glucosidase, cellobiohydrolase, FPase and xylanase, respectively, under shake cultures. The sequence analysis of PCR amplified β-glucosidase gene from wild and mutant showed nucleotide deletion/substitution. The mutants showed highly catalytic efficient β-glucosidase as evident from low Km and high Vmax values. The expression profiling through zymogram analysis also indicated towards over-expression of cellulases. The up/down regulated expressed proteins observed through SDS-PAGE were identified by Peptide mass fingerprinting The cellulase produced by mutants in conjunction with cellulase free xylanase derived from Thermomyces lanuginosus was used for efficient utilization of alkali treated rice straw for obtaining xylo-oligosaccharides and ethanol.
Department of Microbiology, Guru Nanak Dev University, Amritsar 143 005, India. Electronic address: baljit_sohal@rediffmail.com.
Baljit
B
Kaur
Central Institute of Post Harvest Engineering Technology (CIPHET), Ludhiana 141 004, India. Electronic address: hari_manu@yahoo.com.
H S
HS
Oberoi
Department of Microbiology, Guru Nanak Dev University, Amritsar 143 005, India. Electronic address: chadhabs@yahoo.com.
B S
BS
Chadha
D000595:Amino Acid Sequence; D001230:Aspergillus / Q000201:enzymology* / Q000235:genetics*; D002480:Cellulase / Q000096:biosynthesis* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005285:Fermentation; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D010449:Peptide Mapping; D040901:Proteomics; D011523:Protoplasts / Q000378:metabolism*; D003313:Zea mays / Q000737:chemistry; D001617:beta-Glucosidase / Q000737:chemistry / Q000378:metabolism
D001617:beta-Glucosidase; D002480:Cellulase
Cellulase hyper-producer; Cyclic mutagenesis; Fermentation; Hydrolysis; Peptide mass fingerprinting