Lytic enzyme activity in autolysing mycelium of Aspergillus niger

✍ Scribed by Dr. R. Lahoz; Fuensanta Reyes; P. Gómez; M. J. Martinez

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 560 KB
• Volume: 23
• Category: Article
• ISSN: 0233-111X
• DOI: 10.1002/jobm.19830230104

✦ Synopsis

We have studied changes in the activity of some lytic enzymes contained in mycelium of Aspergillus niger in cultures relative to the autolytic phase of growth. Acid phosphatase, polygalacturonidase and a-amylase activity reached its highest level (40.7, and 8 U/sample, respectively) at the initiation of the autolytic phase of growth. 1,3-/3-Glucanase and j3-N-acetylglucosaminidase reached its highest level (3.5 and 2 U/sample, respectively) during the first days of autolysis.

Alkaline phosphatase, cellulase, invertase, esterase, chitinase and proteolytic activity is also present in autolysing mycelium of A. niger, though comparatively low. Their maximum activity coincided with the beginning of the autolytic phase of growth. I n all enzymes studied here, as autolysis proceeded, enzyme activity decreased by about 90%. Only esterase activity remained nearly constant throughout the whole period of autolysis described here.

Changes in lytic enzyme activity in fungal mycelium relative to the autolytic phase of growth have seldom been studied over extended periods of incubation. Thus, BRUNNER et al. (1971) working with Penicillium chrysogenum observed that excretion of proteinases into the culture fluid did not occur before marked autolysis had set in. found that 2 or 3-day old post-autolytic cultures of Aspergillus nidulans showed maximum activity for /3-1,3-glucanase. The fungus Humicola lanuginosa produced maximum amylase activity during the autolytic phase "long after maximum mycelium was detected" (BARNETT and FERGUS 1971). Similarly, REYES