@article{jaem2014265,
author={{B., Ogbonna C. and A., Ibiene A. and O., Stanley H.},
title={Microbial Population Dynamics during Anaerobic Digestion of Guinea Grass (<i>Panicum maximum</i>)},
journal={Journal of Applied & Environmental Microbiology},
volume={2},
number={6},
pages={294--302},
year={2014},
url={http://pubs.sciepub.com/jaem/2/6/5},
abstract={The effect of rumen fluid on microbial population dynamics during anaerobic digestion of Guinea grass (<i>P</i><i>anicum</i><i> maximum</i>) at ambient condition with respect to time was investigated. A one stage batch-typemesophilic anaerobic digestion system was configured using rumen fluid (RF) as inoculums (AD<SUB>RF</SUB>) and a low solid loading of approximately 7.0% total solid (TS). Physicochemical parameters such as process temperature (PTM<SUB>RF</SUB>), process pH<SUB>RF</SUB>, chemical oxygen demand (COD<SUB>RF</SUB>) and volatile fatty acid (VFA<SUB>RF</SUB>) were monitored with time. Selected indicator microbial populations were monitored by standard cultural enumerations based on metabolic capacity and oxygen sensitivity with respect to time. Furthermore, their respective growth rates and population proportions were determined. Result showed that the average PTM<SUB>RF</SUB> increased from 27.5ˇăC to 35.2ˇăC while average process pH<SUB>RF</SUB> ranged from 6.5 to 7.9 with time, respectively. The COD<SUB>RF</SUB> decreased from 11,250.60 mg/L to 2,865.20 mg/L, while VFA<SUB>RF</SUB> ranged from 1,080.00 mg/L to 4,800.33 mg/L with time, respectively. In terms of metabolic capacity, the populations of cellulolytic bacteria (ACB<SUB>RF</SUB>), lactose fermenting bacteria (LFB<SUB>RF</SUB>) and glucose fermenting bacteria (GFB<SUB>RF</SUB>) ranged from 3.6 x 10<SUP>4</SUP> MPN/ml to 2.9 x 10<SUP>5</SUP> MPN/ml, 3.4 x 10<SUP>4</SUP> MPN/ml to 2.9 x 10<SUP>5</SUP> MPN/ml and 4.4 x 10<SUP>4</SUP> MPN/ml to 4.6 x 10<SUP>5</SUP> MPN/ml respectively with time. The populations of propionate oxidizing bacteria (POB<SUB>RF</SUB>), ethanol oxidizing bacteria (EOB<SUB>RF</SUB>) and acetate oxidizing methanogens (AOM<SUB>RF</SUB>) ranged from 2.9 x 10<SUP>4</SUP> MPN/ml to 2.4 x 10<SUP>5</SUP> MPN/ml, 2.7 x 10<SUP>4</SUP> MPN/ml to 2.1 x 10<SUP>5</SUP> MPN/ml and 1.4 x 10<SUP>4</SUP> MPN/ml to 2.1 x 10<SUP>5</SUP> MPN/ml respectively with time. In terms of O<SUB>2</SUB>-sensitivity, the populations of obligate anaerobic bacteria (OAB<SUB>RF</SUB>) and facultative aerobic and anaerobic bacteria (FAAB<SUB>RF</SUB>) ranged from 2.12 x 10<SUP>5</SUP> CFU/ml to 4.53 x 10<SUP>6</SUP> CFU/ml and 4.6 x 10<SUP>5</SUP> CFU/ml to 4.74 x 10<SUP>6</SUP> CFU/ml respectively with time. The population of GFB<SUB>RF</SUB> had the highest growth rate of 0.057 day<SUP>-1</SUP> while the population of EOB<SUB>RF</SUB> had the lowest growth rate of 0.021 day<SUP>-1</SUP>. In terms of O<SUB>2</SUB>-sensitivity, the population of FAAB<SUB>RF</SUB> had the highest growth rate of 0.051 day<SUP>-1</SUP> compared to the population of OAB<SUB>RF</SUB> with growth rate of 0.040 day<SUP>-1</SUP>. The population of GFB<SUB>RF</SUB> predominated (26.3%), while the population of AOM<SUB>RF</SUB><SUB> </SUB>were the minority (10.44%). In terms of O<SUB>2</SUB>-sensitivity, the population of FAAB<SUB>RF</SUB> predominated (56.73%) compared to the population of OAB<SUB>RF</SUB> (43.23%). Rumen fluid significantly (p &lt; 0.05) increased the microbial populations inside AD<SUB>RF</SUB><SUB> </SUB>with respect to time. Therefore, rumen fluid could be used to boost the microbial population in anaerobic digesters as this could enhance depolymerisation, obtain higher degradation rates of cellulosic (or lignocellulosic) substrates and thus higher energy (biogas/methane) benefits.},
doi={10.12691/jaem-2-6-5}
publisher={Science and Education Publishing}
}