African Journal of Soil Science

African Journal of Soil Science ISSN 2375-088X Vol. 6 (7), pp. 466-470, July, 2018. © International Scholars Journals

Full Length Research Paper

Evaluation of isolate yeast strains producing amylolytic enzymes and characterization of the strain productivity and the enzyme produced

Bertrand Tatsinkou Fossi¹, Frédéric Tavea¹ and Robert Ndjouenkeu^1*

Department of Food Science and Nutrition, University of Ngaoundéré, P.O.Box 455 Ngaoundéré, Cameroon.

*Corresponding author. E-mail: [email protected].

Accepted 05 March, 2017

Abstract

An amylolytic yeast strain was isolated from starchy soils (flour mills environment, flour market, cassava farms after harvesting and transformation of tubers) and its enzyme productivity and activity evaluated. The enzyme synthesis was optimum at 30°C when initial pH of fermentation medium was 4.5. After extraction and partial purification, the enzyme remained stable in a range of temperature and pH between 20°C-60°C and 2-8 pH respectively. The optimum enzyme activity was displayed at 70°C and pH 5.5 and 6.5. The thermostability of the enzyme was comparable to that of amylases from bacteria.

Key word: Amylolytic yeast, amylase activity, thermostable amylase.

African Journal of Soil Science ISSN 2375-088X Vol. 6 (8), pp. 471-484, August, 2018. © International Scholars Journals

Full Length Research Paper

Effect of mycorrhizal infection and rock phosphate on plant accumulation and tolerance of heavy metals spiked to the soil

Gamal Hassan Rabie

Botany Department, Faculty of Science, Zagazig University, Egypt.

Corresponding author  E-mail: [email protected]. Fax: +966-3-5817030. Mobile: 00966507407567.

Accepted 07 January, 2017

Abstract

The researcher had investigated the role of arbuscular mycorrhizal fungal inoculation in red kidney and wheat in heavy metals tolerance in soil artificially contaminated with high concentrations of zinc, copper, lead and cadmium. Metals accumulated by mycorrhizal wheat plants were mostly distributed in root tissues, suggesting that an exclusion strategy for metal tolerance widely exists in them. Mycorrhizal red kidney plants could accumulate relatively high metal concentrations in their shoots which indicated that internal detoxification metal tolerance mechanisms are also included. From a number of physiological indices measured in this study, mycorrhizal symbiosis significantly increased root and shoot dry weight, chlorophyll content and total lipid in wheat plants. It also significantly increased root and shoot dry weight, protein content and the activity of antioxidant enzymes in red kidney plants, when the two plant species are grown at heavy metals artificially contaminated soils. The beneficial effects of the Am fungus observed in this study aroused an interest in considering the role of arbuscular mycorrhizal fungi in plant-based strategies of remediation of highly heavy metal contaminated soils.

Key words: antioxidant, chlorophyll, dry weight, mycorrhiza, phosphor, phytoremediation, pollution, symbiosis

African Journal of Soil Science ISSN 2375-088X Vol. 6 (4), pp. 447-452, April, 2018. © International Scholars Journals

Full Length Research Paper

Antibacterial activity of some actinomycetes isolated from farming soils of Turkey

Mustafa Oskay*, A. Üsame Tamer and Cem Azeri

Biology Department, Faculty of Sciences and Arts, Celal Bayar University, Campus of Muradiye, 45030, Manisa, Turkey.

*Correspondingauthor. E-Mail: [email protected].

Accepted 09 January, 2017

Abstract

A total of 50 different actinomycete strains were recovered from farming soil samples collected from Manisa Province and its surrounding. These were then assessed for their antibacterial activity against four phytopathogenic and six pathogenic bacteria. Results indicated that 34% of all isolates are active against, at least, one of the test organisms; Agrobacterium tumefaciens, Erwinia amylovora, Pseudomonas viridiflova, Clavibacter michiganensis subsp. michiganensis, Bacillus subtilis ATTC 6633, Klebsiella pneumoniae ATTC 10031, Enterococcus feacalis ATCC 10541, Staphylococcus aureus ATCC 6538, Esherichia coli ATCC 29998 and Sarcina lutea ATCC 9341. According to antibacterial activity and spectrum broadness, seven of the isolates were selected and characterized by conventional methods. The unusual antibiotic profile of these isolates underlined their potential as a source of novel antibiotics.

Key words: Streptomyces, soil, characterization, antibacterial activity, screening.

African Journal of Soil Science ISSN 2375-088X Vol. 6 (10), pp. 490-493, October, 2018. © International Scholars Journals

Full Length Research Paper

Symbiotic effectiveness of some pH tolerant Bradyrhizobium japonicum strains in low nutrient sandy soil

M. K. Meghvansi, Kamal Prasad* and S.K. Mahna

Department of Botany, Maharshi Dayanand Saraswati University, Ajmer, Rajasthan-305009, INDIA.

*Corresponding author. E-Mail: Tel: +91-98284 80757, [email protected].

Accepted 04 January, 2017

Abstract

Eight strains of Bradyrhizobium japonicum were isolated from the root nodules of soybean cultivar PK 472 collected from Adaptive Trial Centre, Bundi, India. All the isolates were authenticated through plant assay test in germination pouches. Growth of the isolated strains on different pH levels was observed and three strains namely Bj-3, Bj-5 and Bj-8 were found to be able to grow up to pH 8.5. Symbiotic efficiency of these isolates was determined under the mist house conditions in the sterilized sandy soil (pH 8.4). Maximum and minimum nodulation and vegetative growth were observed in Bj-3 and Bj-2 inoculated soybean plants, respectively. Three pH tolerant strains could also pose better results in the efficiency determination experiment. Considerable variability in terms of the symbiotic effectiveness was found in the tested strains.

Key words: Identification, symbiotic effectiveness, Bradyrhizobium japonicum, pH, soybean, nutrient, soil.

African Journal of Soil Science ISSN 2375-088X Vol. 6 (6), pp. 459-465, June, 2018. © International Scholars Journals

Full Length Research Paper

Hydrolyzing several raw native tubers starches with crude amylase Aspergillus niger AM07 isolated and selected from the soil

Omemu, A. M. ¹*; Akpan, I ¹; Bankole, M. O. ¹ and Teniola, O. D. ²

¹Department of Microbiology, University of Agriculture, PMB 2240, Abeokuta, Nigeria.

²Biotechnology Division, Federal Institute of Industrial Research, Oshodi (FIIRO), PMB 21023 Ikeja, Lagos, Nigeria.

*Corresponding author. E-Mail: [email protected]. Tel: +234 8023218008/ 8033271444.

Accepted 03 April, 2017

Abstract

Eight Aspergillus niger strains which produced strong starch degrading amylase were isolated from the soil using a medium containing Remazol Brilliant Blue (RBB) starch as substrate. Amylase production was detected by the disappearance of the blue colour around the colony. Among the isolates, A. niger AM07 produced the largest clear zone (7.0mm) on Remazol Brilliant Blue (RBB) agar plate and also gave the highest amylase yield (806 U/ml) in solid-state fermentation process, hence it was selected for further studies. The crude amylase preparation of A. niger AM07 had temperature and pH optima activities at 60^o C and 4.0 respectively. The optimum substrate concentration was 3 %. The action of the crude amylase of A. niger on raw tuber starches of yam, cassava, sweet potato and cocoyam were studied in comparison with the well known maize starch which is a cereal starch. The crude amylase was able to hydrolyze all the raw starches tested. Hydrolysis was significantly (p<0.05) dependent on starch source and length of incubation. At 72-h incubation time, raw cassava starch gave the highest yield of 200.1 mg/g with a conversion efficiency of 198.91% while raw maize starch gave a yield of 109.6 mg/g with 108.95 % conversion efficiency. Raw cocoyam starch was more resistant to hydrolysis and incubation of cocoyam starch beyond 24 h, resulted in decreased yield of reducing sugars. Thin layer chromatography showed glucose as the main sugar produced with low level of maltose.

Key words: Amylase, Remazol Brilliant Blue, tuber starches, and hydrolysis.