Evaluation and Optimization of Agro-industrial Wastes for Conidial Production of Metarhizium and Beauveria Isolates under Solid State Fermentation
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Date
2015-01
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Addis Ababa Universty
Abstract
Two isolates of Beauveria and three isolates of Metarhizium were grown on different
agricultural wastes to evaluate their conidia production potential under SSF system.
Coffee husk, Tea waste, Wheat bran and Vegetable wastes were used as substrates to
determine maximum conidiation of the isolates. Among these vegetable wastes were the
best medium to yield 5.77±1.53 (107), 5.80±0.72 (107), 4.44 ± 0.55(107) and 5.58 ± 0.66
(107) conidia/gram of substrate under quantitative assessment for isolates (AUBI2,
AUMI1, AUMI2 and AUMI3 respectively) at 60% moisture content. The highest conidia
count record of AUBI1 6.34 ± 2.27 (107) conidia/gram was obtained at 60% moisture
content on wheat bran. It has been observed that two sample t-Test statistical analyses of
conidial yield of vegetable wastes was significantly different from 2mm and 4mm particle
size of coffee husk used as substrates. The optimization for temperature indicated that all
substrates supported maximum conidia yield with-in the range of temperature from 27 to
300
C. Beauveria isolate AUBI1 was produced 11.63 ± 8.34 (107) conidia/gram of
substrate at coffee husk when treated at 3.5 pH value. The pH values used in the present
study for optimization best favored only for coffee husk as substrate. The high conidia
yielding substrates were best productive at their own natural at 6.29 for Vegetable
wastes, 6.63 for Wheat bran and 5.4 for Tea waste pH values. Vegetable wastes
supported AUBI1, AUBI2, AUMI1, AUMI2 and AUMI3 to produce high conidia yield of
4.31 ± 1.18 (107), 5.07 ± 0.76 (107), 3.43 ± 0.30 (107), 1.86 ± 0.16 (107) and 5.17 ± 0.61
(107) conidia/gram of substrate at optimum incubation period of 21 days. The optimum
incubation period of the fungal isolates on wheat bran is 3 - 4 weeks under sufficient
exposure to light. AUBI1, AUBI2 and AUMI1 produce high conidia under exposure to
light but AUMI2 and AUMI3 at dark condition when cultivated on vegetable wastes.
Therefore, as successful microbial control of insect pests depends on cheap and large
scale industrial productivity, entomopathogens cultivation on vegetable wastes and wheat
bran can be attained by SSF system.
Key words: Beauveria, Metarhizium, Inoculation, Optimization and Conidia
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Keywords
Beauveria, Metarhizium, Inoculation, Optimization and Conidia