MICROBIAL AND PHYSICOCHEMICAL ANALYSIS OF AGRO-WASTE USED AS MANURE

ABSTRACT
The organic waste materials used in the present study were orange peels, sawdust, and
poultry droppings. Pour plate technique was used to identify possible bacterial and fungal
isolates. Molecular techniques were used to further identify bacteria isolates. Virulence
properties for the isolates were evaluated. Antibiotic susceptibility, multiple antibiotic
resistance index and plant growth promoting properties of the isolates were evaluated.
The physicochemical and nutritional composition of the waste samples were evaluated
and data were statistically analysed.
The results showed that the total heterotrophic bacterial count of the waste samples
ranged from 4.20 ± 0.06 to 5.10 ± 0.04. The fungal counts ranged from 3.86 ± 0.04 to
4.15 ± 0.02. Identified bacteria included Enterobacter cloacae, Serratia marcescens,
Klebsiella oxytoca, Bacillus subtilis, Staphylococcus aureus, Bacillus cereus, Bacillus
mycoides and Proteus vulgaris.The isolated fungal species were Aspergillus niger,
Trichoderma viride, Penicillium italicum and Rhizopus arrhizus. The physicochemical
analysis revealed that the pH ranged from 6.15 ± 0.18 to 6.91 ± 0.18, moisture from 12.00
± 1.34% to 46.37 ± 0.21% and crude protein from 10.53 ± 0.03% to 22.27 ± 2.15%. The
potassium content ranged from 233.00 ± 3.50mg/kg to 354.53 ± 2.37mg/kg and
phosphorus from 263.53 ± 4.37mg/kg to 763.53 ± 0.37mg/kg. Regarding bacterial
virulence, S. aureus exhibited all analyzed properties compared to other isolates. The
bacterial isolates showed resistance to certain antibiotics, with a multiple antibiotic
resistance index greater than 0.2. After curing, the results indicate that the antibiotic
resistance of S. aureus and Enterobacter cloacae was not plasmid-mediated relative to
the other bacterial isolates. Moreover, most bacterial isolates displayed plant growthpromoting
properties like nitrogen fixation, ammonia production, and phosphate
solubilization. All fungal isolates were capable of indole acetic acid production and
phosphate solubilization. The study underscores the need for informed waste management
practices as well as continued research to safeguard both human health and the
environment.