Production and Characteristics of Raw-Starch-Digesting α-Amylase from a Protease-Negative Aspergillus ficum Mutant

Abstract

Mutational experiments were carried out to decrease the protease productivity of Aspergillusficum IFO 4320 by using N-methyl-N'-nitro-N-nitrosoguanidine. A protease-negative mutant, M-33, exhibited higher aamylaseactivity than the parent strain under submerged culture at 30°C for 24 h. About 70% of the total a-amylase activity in the M-33 culture filtrate was adsorbed onto starch granules. The electrophoretically homogeneous preparation of raw-starch-adsorbable a-amylase (molecular weight, 88,000), acid stable at pH 2, showed intensive raw-starch-digesting activity, dissolving corn starch granules completely. The preparation also exhibited a high synergistic effect with glucoamylase I. A mutant, M-72, with higher protease activity produced a raw cornstarch-unadsorbable a-amylase. The purified enzyme (molecular weight, 54,000), acid unstable, showed no digesting activity on raw corn starch and a lower synergistic effect with glucoamylase I in the hydrolysis of raw corn starch. The fungal a-amylase was therefore divided into two types, a novel type of raw-starch-digesting enzyme and a conventional type of raw-starch-nondigesting enzyme.

Production and Characteristics of Raw-Potato-Starch-Digesting α-Amylase from Bacillus subtilis 65

“…As reported previously (9), a protease-negative mutant of Aspergillus ficum, M-33, produced a novel type of rawstarch-adsorbable, raw-starch-digesting oa-amylase, ox-amylase I (molecular weight, 88,000), but a hyperprotease mutant, M-72, from the same parental strain produced a conventional raw-starch-unadsorbable, raw-starch-nondigesting c.-amylase, cx-amylase II (molecular weight, 54,000).…”

“…We therefore concluded that the fungal cx-amylase was divided into two types: raw-starch-digesting oa-amylase I and raw-starch-nondigesting a-amylase II. Thus, there are many fungal oa-amylases and fungal glucoamylases (9). These results suggested that there might be two types of bacterial ox-amylase as well, raw-starch-digesting and raw-starch-nondigesting.…”

Production of Amylase Enzymes by Filamentous Fungi

“…It is worthy to mention that some isolates of the same species variable degrees of amylase production and this depend on the individual isolates. Table (I) Several of the above species were previously recorded as amylase producers, but with different degrees , as reported by numerous researchers (Prescot & Dunn, 1959 ;Ueda,1981;Hayashida & Teramoto , 1986 ;Bunni et al, 1989;Jensen & Olsen, 1992;Sudo et al, 1995;Okolo et al, 1995;Carlsen et al, 1996 a to c;Kaneko et al, 1996 ;Chadha et al, 1997;Arnesen et al, 1998;Goto et al, 1998 ;Nguyen et al, 2000 ;Pederson & Nielson, 2000;Vishwanathan & Surlikar, 2001 ;Aquino et al, 2003;Francis et al, 2003;Moreira et al, 2004 ;Kunamneni et al, 2005 ;Patel et al, 2005;Rahardjo et al, 2005 ;Samborska et al, 2005;Schwab , 2007;Afifi et al, 2008 andRojas et al ., 2008 andseveral others) .…”

Psychrophilic yeasts and their biotechnological applications - A review

“…Amylases have been found in many yeast species (Gupta et al, 2003;De Mot et al, 1984) including Lipomyces kononenkoae (Prieto et al, 1995), Schwanniomyces alluvius (Wilson and Ingledew, 1982;Moranelli et al, 1982), Trichosporon pullulans (De Mot and Verachtert, 1986), Candida antarctica (De Mot and Verachtert 1987) and C. flavus (Wanderley et al, 2004). A cold active α-amylase from Antarctic psychrophile Alteromonas haloplanktis was reported to exhibit maximum α-amylase production at 4°C (Ramachandran et al, 2004;Hayashida and Teramoto, 1986;Moller et al, 2004). A mutant strain of yeast (S. cerevisiae) has been found to secrete amylases (Wang et al, 2001).…”