Amylase hyper-producing haploid recombinant strains ofThermomyces lanuginosusobtained by intraspecific protoplast fusion

Abstract

Amylase hyper-producing, catabolite-repression-resistant, recombinant strains were produced by intraspecific protoplast fusion of thermophilic fungus Thermomyces lanuginosus strains, using well-characterized, morphological, and 2-deoxy-D-glucose resistant markers. The fusant heterokaryons exhibited enhanced amylase activities as compared to the amylase hyper-producing parental strain (T2). Diploids derived from heterokaryons segregated to stable haploid recombinant strains. In the haploid strain (Tlh 4q), approximately 5-fold higher specific activities of alpha-amylase and glucoamylase in the culture filtrate were observed as compared to the wild-type strain (W0).

Enhanced saccharification of corn straw pretreated by alkali combining crude ligninolytic enzymes

“…These were in good agreement with other studies. 22,39,40 The colonies germinating from YJ9 protoplasts were then screened by clamp connection observation and DCPI staining to identify monokaryons. 25 Approximately 83 colonies were screened and only 14 were shown to be monokaryotic.…”

Pectinase and polygalacturonase production by a thermophilic Aspergillus fumigatus isolated from decomposting orange peels

“…The strain A. fumigatus TF3 was able to grow optimally at 50ºC and also produced maximum amount of pectinase at 50ºC. Thermophilic fungi have been reported to optimally produce enzymes at 50ºC (22,23). Loudiere et al, (15) reported higher temperatures for optimum activity, 50-60ºC for only 20% activity was quantified.…”

“…Using semi-quantitative plate assay approach, a thermophilic fungal strain TF3 (Aspergillus fumigatus MTCC 4163) isolated from decomposing orange peel waste, was selected as the best producer of pectinase and PG. The plate assay approach has been previously employed in our lab for isolating hyper amylase producing mutants/fusants of thermophilic fungus Thermomyces lanuginosus (22,23).…”

“…The potency index of each isolate was calculated as the ratio of zone diameter to colony diameter. The cultures showing high potency index were further screened by semiquantitative plate assay method (22,23). The cultures were individually plated on YPSS medium (9) containing pectin in place of starch and incubated at 50ºC.…”

Genetic Improvement of Fungal Pathogens

“…These evaluations were performed twice. Complementation was evaluated by a dual culture technique on MM plates, and it was ascertained if an aerial mycelium was formed at the contact zone between two distinct nit mutants [16][17][18].…”