각종곡류 및 발효식품에서 분리된 진군류의 분류 및 Amylase 생성능에 관한 연구

Abstract

[한글]

[영문]

Introduction

Many kinds of fungi are distributed in nature and they have close and complicated

relationship with animals and plants.

Among the fungi, some are useful to mankind and some are harmful.

Especially, some kinds of fungi are used for preparation of oriental food. But,

since the discovery of fungal metabolites that are hepatotoxic and carcinogenic,

the importance of fungi inhabiting various kinds of foodstuffs has been increasing

in the field of the food hygiene, agricultures and social affairs. The problem of

mycotoxicoses has now a world wide significance in term of public health.

In 1961, Sargeant et al associated toxicity with mold infestation of feedstuffs

and demonstrated that toxic compounds were produced by certain strain of

Aspergillus flavus isolated from such meals, and nomencletared the generic name

"aflatoxin".

In recent, many investigators were also domonstrated various mycotoxins from

numerous kinds of grains and fermented foods.

Miyake et al (1966), Tsunoda (1950, 1951) and Feuell (1966) were found out

islanditoxin from Pencilium islandicum, Penicillium tocicarium, Penicillium

citrinum, and alleroft and Carnagham (1963) also demonstrated ochratoxin from

certain strain of Aspergillus ochraceus.

Nowadays, some workers reported that Fusarium sp., Cladosporium sp., Alternaria

sp. and Helminthosporium sp. can be secreted several kinds of toxic substances.

It is important that to determine the prevalence of toxin producing fungi from

various grains and fermented pastes and how to prevented of toxin contemination of

foodstuffs.

A serious studies were made on the clssification of fungi isolated from various

grains and fermented pastes and amylase producing activities were tested.

Materials and Methods

A. Materials:

Total of 35 samples of various grains and 10 samples of bean-pastes. There were

collected from Kyunggi Do and Kyungsang-puk Do.

All of the samples were collected from February, 1969 to August, 1969. to August,

1969.

B. Methods:

1. Isolation of Fungi: Prior to culturing, all of the samples were washed

asceptically with sterile distilled water to removed surface contaminates. And

then, the samples were cultured on Czapek-Dox medium contraining 100 mg per liter

of chloramphenicol to suppress becterial growth.

Five grains were placed into each 10 petridishes. These dishes were incubated at

25℃, and daily inspected. All isolates were transfered to slants of Czapek-Dox

media and used for identification of fungi.

2. Identification of fungi: Microscopic observation with slide culture method,

macroscopic observation of colonial morphelogy and biochemical characteristics were

examined to further identification of fungi.

3. Amylase activity test: Culture broth were used for enzyme solution which were

inclubated for ten days on Czepek-Dox media containing 1 per cent starch.

The reaction mixture containing 1 ml of the substrate ( 1 per cent starch

solution), 1 ml of the enzyme solution and 2 ml of phosphate buffer solution was

incubated at 50℃ for 3 hours. After the incubation period the dinitrosalicylic

acid reagent added and boiling for 10 minutes.

Amylase activity was estimated the liverated reducing group by

photoelectro-colorimeter.

Results and Conclusions

1. Of the 35 various grains, fungi were isolated 446 colonies. Among the 446

colonies, it was possible to identify 423 colonies with 17 genera of fungi, 23

colonies could not be identified.

2. Of the 10 bean-pastes, fungi were isolated 193 colonies. It can be identified

11 genera of fungi.

3. It will be noted that Aspergillus sp., Penicillium sp., Mucor sp.,

cladosporium sp. were predominated genera.

4. A total of 155 colonies of Aspergillus sp. isolated from various grains were

obtained from the samples. Asp. versicolor was the frequent species and 47 colonies

isolated.

5. Penicillium, woere was isolated from various grains obtained 115 colonies.

Pen. camemberti was the most frequent species.

6. Penicillium palitans was most excellent amylase producing fungi and which was

1 ml per 6,300 unit.