Influence of spore concentration on microorganism morphology and on glucoamylase production in submerged cultures of Aspergillus awamori

• Published in: Brazilian journal of microbiology 2000-10, Vol.31, p.49-54
• Main Authors: Pamboukian, CRD, Facciotti, MCR, Olivo, JE, Badino, ACB Jr, Schmidell, W
• Format: Article
• Language: English
• Subjects: Aspergillus awamori; Glucoamylase
• ISSN: 1517-8382

The influence of the spore concentration in the inoculum preparation on microorganism morphology and glucoamylase synthesis by submerged cultures of Aspergillus awamori was investigated. A series of fermenter runs were performed, using an initial total reducing sugar concentration of 40 g/L. The inocula were prepared in a rotatory shaker, at 35 degree C and 200 rev/min for 24 hours, varying spore concentration in the flasks from 9.5 times 10 super(3) to 1.8 times 10 super(7) spores/mL. The inocula prepared with a spore concentration between 9.5 times 10 super(3) spores/mL and 5.0 times 10 super(6) spores/mL were composed by a cell suspension mainly in the pellet form, which led to a filamentous growth in the fermenter. Glucoamylase production was not affected by this range of spore concentration, reaching values between 2,100 U/L and 2,300 U/L. However, a higher spore concentration in the inoculum preparation (1.8 times 10 super(7) spores/mL) led to a inoculum formed by a cell suspension in the filamentous form containing many spore agglomerates (non-germinated spores). This kind of inoculum led to a growth predominantly in the pellet form in fermenter, which reduced the glucoamylase production in 30%.