Assiut Univ. J. of Botany

38(2), P-P. 93-106 (2009)

HEAT-RESISTANT FUNGI ISOLATED FROM SOIL IN MINIA

GOVERNORATE, EGYPT

Ali M.Ali, Soaad Moghazy, Gehan Shaban, Zainab El- Sababty

Department of Botany and Microbiology, Faculty of Science, Minia

University, Minia, Egypt

Received: 16/5/2009

Total of 25 cultivated soil samples were collected from different localities in Minia

Governorate, Southern Egypt to investigate heat resistant fungi. The survival of

heat resistant fungi from soil samples was recorded after heat treatment at 60˚ and

70 °C for 30 min. and 80˚ and 90°C for 10 and 20 min. on 20 % sucrose -Czapek’s

agar .

The least resistant fungi surviving 60° and 70° C for 30 min were Eurotium

amstelodami, Dichotomomyces cejpii,Byssochlamys nivea ,Hamigera avellanea,

Talaromyces stipitatus, T.barcinensis, T.ucrainicus and T. flavus; none of these

survived above these temperatures. At 80°C for 10 min., survival was seen for

Talaromyces trachyspermus, Thermoascus crustaceus Neosartorya spinosa and

Arthrinium sp.; at 80° C for 20 min., only the latter two species could survive .

Aspergillus fumigatus, Emericella nidulans and Trichoderma asperellum survived

heat treatment at 90°C for 10 and 20 min. with the latter two species being the most

resistant. Occurrence of heat resistant fungi should be further investigated from

Egyptian soils.

Key words: Fungi; heat-resistant; soil; Egypt

INTRODUCTION

Heat resistant fungi can be defined as those capable of surviving

temperatures at or above 75°C for 30 or more minutes (Houbraken and

Samson, 2006, 2007), however, other investigators have reported incidence

of heat resistant fungi at 60˚ and 70°C (Ugwuanyi and Obeta, 1991; Jesenská

et al., 1992, 1993; Piecková et al., 1994). They were first reported by Olliver

and Smith (1933) where they identified a fungus named Byssochlamys fulva

isolated from bottled fruit. The fungal structures which can survive these

high temperatures for definite time periods are ascospores, chlamydospores

and thick walled hyphae or sclerotia (Scholte et al., 2000). Importance of

detection and studying the heat resistant fungi is because of their ability to

survive high temperatures and to spoil canned and pasteurized fruit products

that result in huge economic losses.

Heat resistant fungi are widely distributed in the soil which is an

important source of these micromycetes (Beuchat and Rice, 1979; Pitt

1979; Fravel and Adams, 1986; Okagbue, 1989), particularly in

94 Ali M.Ali, Soaad Moghazy, Gehan Shaban, Zainab El- Sababty

vineyards, orchards and fields in which fruits are grown (Put, 1964;

Splittstoesser et al., 1971; Yates, 1974). Byssochlamys nivea Westling,

Neosartorya fischeri (Wehmer) Malloch and Cain, and Talaromyces

flavus (Klöcker) Stolk and Samson (Beuchat, 1986; Eckardt and Ahrens,

1978; Samson, 1989) are the best known heat resistant fungi.

Talaromyces trachyspermus (Shear) Stolk and Samson (Pitt and Hocking,

1985) has also been reported to be heat resistant fungi. Dichotomomyces

cejpii (Mil’ko) D.B. Scott was isolated as heat resistant fungus (Jesenská

et al., 1992, 1993; Piecková et al., 1994). Houbraken et al. (2008)

reported that Paecilomyces variotii is a common cosmopolitan mold

found in soils, indoor environments, plants, animals and foodstuffs and is

frequently encountered in heat treated products.

The objective of this research was to search for heat resistant fungi

in soil in Minia Governorate, Southern Egypt.

MATERIALS AND METHODS

Collection of soil samples

Total of 25 cultivated soil samples were collected from various

localities of Minia Governorate, Southern Egypt. The collection sites

were crops and fruit gardens as shown In (Table 1). Samples were

collected from soil surfaces at depths of not more than 10 cm. Samples

were taken into clean plastic bags and kept in a cool place during storage.

Table 1: Sites from which soil samples were collected, and fruit or crop

type in the 25 soil samples tested.

Sample No. Place Fruit or Crop type

Minia city

1 Abu-felew wheat

2 Safet El-khamar tomato

3 Zawyet Sultan corn

4 Tahnasha grapes

5 Bni- Ahmed soya bean

Mallawi

6 El- Ashmonin grapes

7 El- Mahras banger el-sokar

8 El-sharefeya grapes

9 Etledem wheat

Samalott

10 El-Sharawyeh potatoes

11 Albayahoo grapes

12 Ezpet Feline apple

Heat-Resistant Fungi Isolated From Soil in Minia Governorate, Egypt 95

Table 1: continued

El-Edwa

13 Kafr el-maghrepy wheat

14 Mefawez teiba corn

15 Kafr el-maghrepy mango

Abu-Qurqas

16 Mansafees apple

17 El- Karm grapes

Deir Mawas

18 Tal El-amarna wheat

19 NazLet Said mango

Bni-Mazar

20 Bni-Mazar banana

21 El-gendy apple

Maghagha

22 Bertbat wheat

23 Kafer El-salhin grapes

Mattay

24 Cycle way apple

25 Bardanoha grapes

Isolation of heat resistant fungi

Each soil sample was homogenized before beginning the analysis.

Ten g of each soil samples were aseptically transferred into conical flasks

(500 ml) with 100 ml sterile distilled water. The contents were mixed by

vigorously shaking in a shaker for 30 min, and then 10 ml of this content was

transferred into each of four conical flasks (250 ml) with 40 ml sterile

distilled water to obtain the final dilution 1/50 for four heat treatments of 60˚,

70˚, 80˚, and 90°C. The previous four flasks were exposed to temperatures of

60˚, 70°C for 30 min and 80˚, 90°C for 10, 20 min in a water bath totally

submerged in the water (one with the capability of shaking during heating)

.The water bath should be at the desired heat treatment before the sample is

introduced (Houbraken and Samson, 2006) .After the heat treatment, the

flasks were cooled to approximately 55°C. One ml of each heat treatment

was pipetted aseptically into three replicates (9 cm Petri dishes) and mixed

thoroughly with about 10 ml of molten (approx. 55°C) 20 % sucrose-

Czapek’s agar containing rose-bengal at (150 mg/l) as a bacteriostatic agent

(Baggerman, 1981) .The Petri dishes were placed into a plastic bag to

prevent drying and incubated in an upright position at 30°C in darkness for

14 days (Houbraken and Samson, 2006). After the incubation period

representative fungal colonies were counted ,calculated per gm dry soil in

96 Ali M.Ali, Soaad Moghazy, Gehan Shaban, Zainab El- Sababty

every sample , identified ,purified on PDA plates and preserved on PDA

slants at 4°C .Heat resistant fungi usually form colonies after 5 days and

mature within 14 days at 30°C,so the Petri dishes were checked for the

presence of colonies after 7 -14 days.

Identification of fungal isolates

Most of our fungal isolates were identified by Jos Houbraken,

Member of the Department of Applied and Industrial Mycology at the

(CBS-Fungal Biodiversity Centre, Utrecht, The Netherlands).

RESULTS AND DISCUSSION

I –Fungal species capable of surviving 60° and 70°C for 30 min

The data in Table 2 indicate that 11 species which belong to 7

genera were isolated and identified from soil samples that were exposed

to temperature 60°C for 30 min. Talaromyces was extremely the most

frequent genus. It was collected in all samples with a total count of 540

colonies per gm dry soil representing 38.16 % of the total count of fungi

at this heat treatment (data not shown in tables). Five species of

Talaromyces were recorded of which T.trachyspermus was the most

predominant; it was isolated in high frequency of occurrence (22 cases

with a total count of 195 colonies constituting 13.8 % of total fungi).

T.stipitatus and T.flavus were recovered in 17 and 16 samples,

respectively, while T.barcinensis and T. ucrainicus were identified in 12

and 11 samples, respectively.

The second most frequent genus was Eurotium .One species of the

genus was identified namely, E. amstelodami (24 cases with the highest

population of 405 colonies comprising 28.6 % of total fungi). The well

defined heat resistant fungus Byssochlamys nivea was isolated highly in

this study (20 cases and 140 colonies). Paecilomyces variotii was isolated

in 17 samples. Hamigera avellanea and Dichotomomyces cejpii were

isolated in equal numbers of isolation (15 cases for each). Neosartorya

spinosa was identified in moderate frequency of occurrence (7 cases with

a total count of 75 colonies representing 5.3 % of total fungi) to be the

least isolated fungus at 60°C for 30 min.

The richest soil samples in fungi were No. 11 and 16, where the

total counts were 95 and 90 colonies comprising 6.7 and 6.4 % of total

fungi, respectively. The poorest sample was No. 15 which contained 15

colonies constituting 1 % of total fungi. The fungal contents of other soil

samples fluctuated between these values.

Heat-Resistant Fungi Isolated From Soil in Minia Governorate, Egypt 97

Table 2: Total count (per gm dry soil ) of fungal genera and species in

soil suspensions exposed to 60°C for 30 min, isolated on 20%

sucrose-Czapek's agar incubated at 28 °C ± 2 for 15 days.

NCI

Total count of colonies ⁄ gm dry soil at 60°C for 30 min Species

Sample No. 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

25 15 15 25 20 40 15 10 10 20 40 5 20 15 25 35 20 25 30 25 15 5 25 35 25 25 Talaromyces

22 5 5 15 5 15 10 5 5 10 20 0 15 5 5 10 0 5 10 10 5 0 5 15 5 10 Talaromyces trachyspermus

(Shear) Stolk and Samson

17 5 5 5 5 10 0 0 5 5 5 0 0 5 5 10 10 10 5 0 0 0 0 10 5 5 Talaromyces stipitatu, (Thom)

C. R. Benj

16 0 0 0 5 10 0 0 0 5 10 0 5 5 10 10 5 0 5 5 0 5 10 5 5 5 Talaromyces flavus (Klöcker)

Stolk and Samson

12 5 0 0 5 0 5 5 0 0 5 5 0 0 0 5 5 0 5 5 0 0 5 5 0 0

Talaromyces barcinensis

Yaguchi and Udagawa

11 0 5 5 0 5 0 0 0 0 0 0 0 0 5 0 0 10 5 5 10 0 5 0 10 5

Talaromyces

ucrainicus

(Panasenko)

Udagawa

24 20 20 10 10 20 20 35 5 40 45 0 10 20 20 35 5 5 10 25 5 5 5 15 15 5

Eurotium

amstelodami (Talice & J. A.

Mackinnon)

Kozak 20 5 5 10 10 0 0 10 5 10 5 0 0 10 0 5 5 5 5 10 5 10 5 5 10 5

Byssochlamys nivea Westling

17 0 0 5 5 5 0 5 0 5 0 5 5 10 5 5 5 0 0 5 5 0 5 5 5 5 Paecilomyces variotii Bainier

15 5 5 5 0 0 0 0 5 5 5 5 5 5 0 5 5 0 0 5 5 0 5 5 5 0 Hamigera avellanea Stolk

& Samson

15 5 5 5 5 0 5 5 0 5 0 0 0 5 10 5 5 0 5 5 0 0 0 5 5 0

Dichotomomyces

cejpii (Mil'ko) D.B.Scott

7 5 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 10 15 5 0 35 5 0 0 0

Neosartorya spinosa (Raper

& Fennell) Kozakiewicz

55 50 65 50 65 40 65 25 85 95 15 40 65 60 90 45 45 65 80 35 55 50 70 65 40 Total count

NCI Number of Cases of Isolation 0 Species not observed

Each value indicates the mean of three replicates (plates) for each treatment.

98 Ali M.Ali, Soaad Moghazy, Gehan Shaban, Zainab El- Sababty

Table 3: Total count (per gm dry soil ) of fungal genera and species in

soil suspensions exposed to 70°C for 30 min, isolated on 20%

sucrose-Czapek's agar incubated at 28 °C ± 2 for 15 days.

NCI

Total count of colonies ⁄ gm dry soil at 70°C for 30 min Species

Sample No. 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

25 15 15 15 35 25 15 15 5 10 10 10 35 10 20 20 15 25 15 30 20 10 20 15 20 15 Talaromyces

17 5 5 0 20 5 0 5 5 5 0 0 20 5 5 10 5 10 5 10 0 5 0 0 5 0 Talaromyces trachyspermus

15 5 0 15 0 10 5 5 0 0 5 0 5 5 5 0 5 0 0 5 10 0 5 0 5 5 Talaromyces stipitatus

15 0 0 0 5 5 5 0 0 0 5 0 5 0 5 0 0 10 5 5 10 5 5 5 10 5 Talaromyces

ucrainicus

14 5 5 0 10 5 0 0 0 5 0 5 0 0 5 5 0 5 0 5 0 0 5 5 5 5 Talaromyces

flavus

11 0 5 0 0 0 5 5 0 0 0 5 5 0 0 5 5 0 5 5 0 0 5 5 0 0 Talaromyces

barcinensis

20 10 5 5 10 15 5 5 20 35 10 0 0 15 10 0 5 0 5 10 0 5 5 5 5 10 Eurotium

amstelodami

17 0 0 5 5 5 10 5 5 0 0 5 5 5 5 0 0 0 5 5 10 5 10 5 0 5 Dichotomomyces cejpii

16 0 5 5 5 0 5 0 5 0 5 5 5 0 5 5 0 5 5 0 5 5 5 5 0 0 Paecilomyces variotii

15 5 10 0 0 0 10 0 10 5 10 5 0 0 5 5 5 5 5 0 0 0 0 5 5 5 Byssochlamys

nivea

14 0 10 0 20 0 5 5 0 5 5 5 0 5 0 0 0 5 0 0 45 0 10 5 5 5 Neosartorya

spinosa

14 5 5 0 0 5 5 0 5 5 0 5 5 0 5 5 0 5 0 5 0 5 5 0 0 0

Emericella

nidulans

(Eidam) Vuill.

13 0 0 5 0 5 5 0 0 5 5 5 0 5 5 0 0 5 5 0 0 0 5 5 0 5

Aspergillus

fumigatus

Fresen.

12 0 0 0 0 5 5 0 5 5 0 5 0 5 0 5 0 5 0 5 5 5 0 0 0 5 Hamigera

avellanea

35 50 35 75 60 65 30 55 70 45 45 50 45 55 40 25 55 40 55 85 35 60 45 35 50 Total count

In Table 3 two other species were recorded at 70°C for 30 min in addition

to the isolated species at 60°C for 30 min and these were Emericella

nidulans and Aspergillus fumigatus ;they were of high frequency of

occurrence (14 and 13 cases with total count of 70 and 65 colonies

comprising 5.64 and 5.24 % of total fungi ,respectively).The highest

count of heat resistant fungi (85 colonies) was recorded in sample No. 6

whereas sample No. 10 was the poorest one that contained 25 colonies

representing 6.85 and 2% of total fungi, respectively.

Heat-Resistant Fungi Isolated From Soil in Minia Governorate, Egypt 99

In the 25 soil samples collected from Minia Governorate and

exposed to 60˚ and 70°C for 30 min Eurotium amstelodami was recorded

most frequently; this fungus has not been reported as heat resistant from

soil according to our available knowledge. Talaromyces trachyspermus

and Dichotomomyces cejpii were isolated from most soil samples while

incidence of these two species has been reported sporadic in soil of

Slovak Republic (Jesenská et al., 1992; Piecková et al., 1994). Among the

isolates in the heat treated soil samples that were obtained in high

numbers were Byssochlamys nivea, Paecilomyces variotii, Talaromyces

flavus, T.stipitatus, T.ucrainicus, Aspergillus fumigatus, Emericella

nidulans and Hamigera avellanea. Houbraken and Samson (2006) have

isolated Hamigera avellanea, Paecilomyces variotii, Byssochlamys sp.

and Talaromyces trachyspermus after heat treatment at 75°C for 30 min.

The well-known isolates for spoilage of canned products Byssochlamys

nivea, Neosartorya spinosa, and Talaromyces flavus have been before

investigated (Baggerman, 1981; Hocking and Pitt, 1984; Jesenská et al.,

1984; Jesenská and Petríková, 1985; King, 1986; Scott and Bernard,

1987). Talaromyces barcinensis and T.ucrainicus have not been

previously reported as heat resistant fungi.

II- Fungal isolates capable of surviving 80° and 90°C for 10 and 20 min

Seven species were observed and isolated at 80°C for 10 min

(Table 4). Neosartorya spinosa was the most predominant species and

was recorded in 16 soil samples with a total population of 190 colonies

constituting 37.62 % of the total count of all fungi. Talaromyces

trachyspermus, Emericella nidulans and Fusarium oxysporum were

isolated in 11 cases for each. Aspergillus fumigatus and Arthrinium sp.

were identified in 9 soil samples. Thermoascus crustaceus was isolated

moderately (8 cases which represented 7.92 % of the total count of fungi)

.Samples No.12 and 22 were the richest soil samples in their fungal

contents whereas sample No. 13 contained the least count of heat resistant

fungi comprising 6.9 and 0.9% of the total count of fungi, respectively.

100 Ali M.Ali, Soaad Moghazy, Gehan Shaban, Zainab El- Sababty

Table 4: Total count (per gm dry soil ) of fungal genera and species in

soil suspensions exposed to 80°C for 10 min, isolated on 20%

sucrose-Czapek's agar incubated at 28 °C ± 2 for 15 days.

NCI

Total count of colonies ⁄ gm dry soil at 80 °C for 10 min Species

Sample No. 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

16 15 10 20 25 0 5 0 15 5 0 10 0 5 15 10 0 5 0 5 20 0 0 20 0 5 Neosartorya spinosa

11 0 5 5 0 5 0 0 5 5 0 0 5 0 5 0 5 0 5 0 0 5 0 0 5 0 Talaromyces

trachyspermus

11 0 5 0 5 0 0 0 5 0 0 5 0 0 5 5 0 5 5 0 0 0 5 0 5 5 Emericella nidulans

11 10 5 0 0 5 0 10 0 5 5 0 5 0 10 0 0 0 5 0 0 10 5 0 0 0

Fusarium oxysporum

(Link) Wollenw.

9 0 0 0 5 0 0 5 0 0 5 5 0 0 0 5 0 0 5 5 0 0 5 5 0 0 Arthrinium sp.

9 5 5 0 0 0 0 0 0 0 5 5 5 0 0 0 0 0 5 0 0 5 5 5 0 0 Aspergillus

fumigatus

8 0 0 0 0 0 5 5 0 5 0 0 0 0 0 5 5 0 0 5 0 0 0 0 5 5

Thermoascus crustaceus

(Apinis &

Chesters) Stolk

30 30 25 35 10 10 20 25 20 15 25 15 5 35 25 10 10 25 15 20 20 20 30 15 15 Total count

Table 5: Total count (per gm dry soil ) of fungal genera and species in

soil suspensions exposed to 80°C for 20 min, isolated on

20% sucrose-Czapek's agar incubated at 28 °C ± 2 for 15 days.

NCI

Total count of colonies ⁄ gm dry soil at 80 °C for 20 min Species

Sample

No. 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

17 10 5 0 5 5 15 0 5 5 0 5 0 0 10 5 0 5 5 5 5 0 5 0 0 5 Emericella

nidulans

15 5 0 5 10 0 5 0 5 5 0 0 0 5 5 5 5 5 0 5 10 0 5 0 5 0 Neosartorya

spinosa

15 0 0 5 0 5 5 5 5 0 5 5 5 5 0 0 0 5 5 5 0 0 0 5 5 5

Trichoderma

asperellum

Samuels, Lieckfeldt &

Nirenberg

14 0 5 5 0 5 0 5 5 0 0 5 5 5 0 0 5 0 5 0 5 5 0 5 0 5

Aspergillus

fumigatus

10 0 0 0 0 0 0 5 0 0 0 5 0 0 0 5 5 0 0 0 5 10 5 5 10 5 Arthrinium sp.

15 10 15 15 15 25 15 20 10 5 20 10 15 15 15 15 15 15 15 25 15 15 15 20 20 Total count

Heat-Resistant Fungi Isolated From Soil in Minia Governorate, Egypt 101

It appears from Table 5 that 5 species were identified at 80°C for

20 min. Emericella nidulans was the most frequently heat resistant fungus

(17 cases constituting 25.64% of total count of fungi) followed by

Neosartorya spinosa and Trichoderma asperellum that were recovered in

15 soil samples for each representing 21.8 and 19.2 % of the total count

of fungi, respectively. Aspergillus fumigatus was identified in 14 soil

samples representing 17.9 % of the total count of fungi. The least frequent

species was Arthrinium sp. (10 cases accounting for 15.4 % of the total

count of fungi). Total count was the highest in samples No. 6 and 20

which contained 25 colonies for each while it was the lowest in sample

No.16 that contained 5 colonies representing 6.4 and 1.28 % of the total

count of fungi, respectively.

Table 6: Total count (per gm dry soil ) of fungal genera and species in

soil suspensions exposed to 90°C for 10 min , isolated on 20%

sucrose-Czapek's agar incubated at 28 °C ± 2 for 15 days.

NCI

Total count of colonies ⁄ gm dry soil at 90°°C for 10 min Species

Sample No.

IsolatesSSp

ec

25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

18 5 5 5 10 0 5 0 5 5 0 5 0 5 5 0 5 5 20 0 10 5 0 5 10 5 Emericella

nidulans

14 0 0 0 5 5 5 5 0 0 5 5 0 5 0 5 5 0 5 5 5 5 0 0 0 5 Trichoderma

asperellum

14 5 5 0 5 5 0 0 5 5 0 0 5 0 0 5 0 0 15 5 5 0 5 5 5 0 Aspergillus fumigatus

10 10 5 20 10 10 5 10 10 5 10 5 10 5 10 10 5 40 10 20 10 5 10 15 10 Total count

The data of Table 6 show that 3 species were isolated from soil

samples which were exposed to 90°C for 10 min .Emericella nidulans

was of high frequency of occurrence (18 cases with a total population of

120 colonies which represent 44.44 % of the total count of fungi). It was

followed by Aspergillus fumigatus and Trichoderma asperellum which

were recovered in 14 soil samples for each constituting 29.6 and 25.9 %

of the total count of fungi. Arthrinium sp. was absent at this treatment.

The richest soil sample was No. 8 which contained 30 colonies

constituting 11% of the total count of fungi.

102 Ali M.Ali, Soaad Moghazy, Gehan Shaban, Zainab El- Sababty

Table 7: Total count (per gm dry soil ) of fungal genera and species in

soil suspensions exposed to 90°C for 20 min, isolated on 20% sucrose-

Czapek's agar incubated at 28 °C ± 2 for 15 days.

NCI

Total count of colonies|/ gm⁄ dry soil at 90°°C for 20 min Species

Sample

No. 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

16 5 5 5 10 0 5 0 0 5 0 5 0 5 5 0 0 5 10 0 15 5 0 5 10 5 Emericella

nidulans

14 0 0 0 5 5 5 5 0 0 5 5 0 5 0 5 5 0 5 5 5 5 0 0 0 5 Trichoderma

asperellum

5 5 5 15 5 10 5 0 5 5 10 0 10 5 5 5 5 15 5 20 10 0 5 10 10 Total count

As shown in Table 7, only 2 species were isolated from soil

suspension heated at 90°C for 20 min. Emericella nidulans was highly

identified in 16 soil samples with a total count of 105 colonies accounting

for 60 % of the total count of fungi while Trichoderma asperellum was

recovered in 14 soil samples. The highest total count of fungi was

recorded in sample No. 6 which contained 20 colonies representing 40%

of the total count of fungi. Samples No. 4, 14, and 18 did not contain any

heat resistant fungus at this treatment.

The incidence of heat resistant fungi in the 25 soil samples that

were exposed to temperatures of 80° and 90°C for 10 and 20 min ranged

between high and moderate. Among the isolates in the heat treated soil

samples occurring in high numbers were Emericella nidulans,

Neosartorya spinosa, Aspergillus fumigatus and Trichoderma asperellum.

Okagbue (1989) have described Neosartorya spinosa as the commonest

heat resistant fungus in Northern Nigerian soils in addition to isolation

of A.fumigatus among other important heat resistant fungi, However,

Jesenská et al. (1992,1993) isolated N.spinosa at 80˚ and 90˚C for definite

periods of time in low numbers. Occurrence of Fusarium oxysporum,

Thermoascus crustaceus and Talaromyces trachyspermus was

intermediate. Arthrinium sp. was the least heat resistant fungus. There are

no available records of Thermoascus crustaceus, Arthrinium sp. and

Trichoderma asperellum being heat resistant fungi.

III-Fungal species survived at heat treatments applied in this study

The data in Table 8 enumerate the fungal species that were

recovered from soil samples heated at temperatures of 60˚and 70°C for 30

min and 80˚ and 90°C for 10 and 20 min. Ten species survived mainly at

60˚and 70°C for 30 min namely, Eurotium amstelodami, Byssochlamys

nivea, Dichotomomyces cejpii, Hamigera avellanea, Paecilomyces

Heat-Resistant Fungi Isolated From Soil in Minia Governorate, Egypt 103

variotii ,Talaromyces flavus, T.stipitatus, T.barcinensis T.ucrainicus and

T.trachyspermus ,the latter survived heating at 80°C for 10 min.

Byssochlamys nivea, Dichotomomyces cejpii and Talaromyces flavus

were eliminated at 80°C after 10 min (Jesenská et al.,1993) .

When soil was heated at 80°C for 10 and 20 min the number of

species declined to be eight species , of which was Neosartorya spinosa that

survived heating at 60˚and 70°C for 30 min and 80°C for 20 min ; Fusarium

oxysporum and Thermoascus crustaceus appeared at heat treatment 80°C for

10 min; Arthrinium sp. survived heating at 80°C for 20 min. Aspergillus

fumigatus was observed at treatment 80°C for 10 and 20 min and 90°C for

10 min ,but not 90°C for 20 min . It was obvious that the decreasing number

of species was continual with increasing heat treatments for different time

intervals. Trichoderma asperellum was identified at 80°C for 10, 20 min and

90°C for 20 min. Emericella nidulans appeared at 70°C for 30 min and 80°

and 90°C for 10 and 20 min. Trichoderma asperellum and Emericella

nidulans were considered the most resistant species in this work; they

survived even 90°C for 20 min, whereas Jesenská et al. (1993) have reported

that isolates of Talaromyces avellaneus were the most heat resistant,

surviving 90°C for 60 min in soil.

Table 8: Fungal species surviving heat treatments.

Species 60°C

30 min

70°C

30 min 80 °C 90 °C

10 min 20 min

10 min 20 min

Talaromyces flavus * *

Talaromyces stipitatus * *

Talaromyces barcinensis * *

Talaromyces ucrainicus * *

Talaromyces trachyspermus * * *

Eurotium amstelodami * *

Dichotomomyces cejpii * *

Paecilomyces variotii * *

Byssochlamys nivea * *

Hamigera avellanea * *

Neosartorya spinosa * * * *

Emericella nidulans * * * * *

Aspergillus fumigatus * * *

Fusarium oxysporum *

Thermoascus crustaceus *

Arthrinium sp. * *

Trichoderma asperellum * *

*

*survival (growth) not observed

104 Ali M.Ali, Soaad Moghazy, Gehan Shaban, Zainab El- Sababty

Acknowledgments

We are deeply grateful to Jos Houbraken, Member of the

Department of Applied and Industrial Mycology at the (CBS-Fungal

Biodiversity Centre, Utrecht, The Netherlands) for kindly identifying

most of our isolates.

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____________________

106 Ali M.Ali, Soaad Moghazy, Gehan Shaban, Zainab El- Sababty

عسل الفطرياث الوقاوهت للحرارة هي التربه بوحافظت الويا

زيب السبابط– جيهاى هحود شعباى – سعاد هحود صر هغازي –عل هحود عل

جاهعت الويا– كليت العلىم –قسن الباث والويكروبيىلىجيا

اسخذف زا انبحث حصش ػضل انفطشياث انقايت نهحشاسة ف

ػيت حشب يضسػت حى جؼا ي ياطق يخخهفت ف يحافظت انيا 25

أظشث انفطشياث انؼضنت ي انخشب يقذس ػه انقاي .بجب يصش

دقيقت كزنك 30 دسج نذة 60,70 بؼذ انؼايه بانحشاس ػذ دسجاث

-سكشص %20 دقيق ػه سط غزائ 10,20 دسج نذة 90 ,80

.شابكس أجاس

دسج نذة 60,70أظشث انذساس أ انفطشياث األقم يقاي ػذ

, داكحيييسيس سيجيبي,دقيقت كاج فطشياث إسحيو ايسخهداي30

حاالسييسس ,حاالسييسس باسسييسس , اييجيشا أفياليا ,بيسكالييس يفيا

أكشاييكس حاالسييسس فالفس أ أيا ي ز انفطشياث نى يخحم انقاي ف

دسج حشاس أػه ي رنك قذ أظشث فطشياث حاالسييسس

يساسحسيا اسبيصا ع اسثيو يقذسة ,كشاسخيس ثيشياسكس,حشاكيسبشيى

دقائق نكا نى حسخطغ انقايت 10 نذة 80ػه انقايت ػذ دسجت حشاسة

ع اسثيو فقذ اسخطاػج انقايت , دقيقت ياػذا يساسحسيا اسبيصا 20ػذ

كزنك أظشث انذساست يقذسة فطشياث اسبشجهس . دسجت 80 دقيقت ػذ 20ػذ

إييشسيال يذيالس حشايكديشيا اسبيشيهيى ػه ححم دسجت ,فيييجاحس

.دقيق أ انػي األخيشي كاا األكثش يقايت 10,20 دسج نذة 90 انحشاسة

إ انفطشياث انقايت نهحشاسة انؼضنت ي انخشبت انصشيت ف حاجت شذيذة

.نضيذ ي انذساساث نؼشفت انكثيش ي خاصا انت

Assiut Univ. J. of Botany

38(2), P-P. 93-106 (2009)

Assiut Univ. J. of Botany

38(2), P-P. 93-106 (2009)