Agriculture Reference
In-Depth Information
Table 12.1 Microbial population during mesophilic composting of agro-industrial waste.
(Adopted and modified f rom: Pepe et al. 2013 )
Microbial functional
group
Microbial count (cfu g −1 ) at different time interval
0 days
23 days
123 days
Total aerobic bacteria
6.8-6.9
7.0-7.3
8.1-8.2
Total anaerobic
bacteria
7.5-6.8
4.0-5.7
7.1-7.1
Mold and yeast
5.3-5.0
4.9-6.4
5.2-5.0
Actinobacteria
7.2-7.4
3.7-5.5
3.6-3.7
Proteolytics
4.0-4.6
3.9-4.8
3.5-3.3
Ammonifiers
4.3-5.6
3.8-3.9
5.0-5.0
N 2 fixing aerobic
6.2-6.4
3.2-5.5
3.4-3.7
N 2 fixing anaerobic
4.5-3.8
1.9-4.7
2.2-3.0
Ammonia oxidizing
2.9- < 0.5
3.3- < 0.5
< 0.5- < 0.5
Nitrite oxidizing
2.3- < 0.5
3.7-5.3
4.7-6.4
Nitrate reducing
2.8-2.9
4.6-4.4
4.2-4.3
Amylolytics
5.8-5.6
5.6-7.8
7.9-8.1
Pectinolytics
6.9-7.7
5.3-7.9
5.5-8.0
Cellulolytics
5.0-4.9
5.5-6.5
7.3-8.0
As 2 O 3 ) mg kg −1 on dry mass basis 10.00, cadmium (as Cd) 5.00, Chromium (as Cr)
50.00, Zinc (as Zn) 100.00, and mercury (as Hg) should be 0.15. Similarly, minimum
total organic carbon by total dry mass should contain 40 %, total nitrogen 0.8 %, total
phosphorus (P 2 O 5 ) 0.4 %, total potassium (as K 2 O) 0.4 % and sum of all i.e., Total
Organic carbon, nitrogen, phosphate and potassium may present at 1.5 %.
12.3
Ecology of Composting
Since composting is mainly involves different genera of microorganisms, commu-
nity dynamics is essential for the process of decomposition. Several groups of cel-
lulytic, pectinolytic, amylolytic and ligninolytic bacteria, fungi and actinobacteria
producing different enzyme are actively involved in process of compost formation.
The bacterial community dynamics of compost, from mesophilic to thermophilic
depends on several factors that directly or indirectly influence the ecology of com-
post (Boulter et al. 2000 ; Taiwo and Oso 2004 ).
Hargerty et al. ( 1999 ) reported that there was maximum increase in microbial pop-
ulation in the early stages of composting which was dependent on intial substrate used
and environmental conditions of composting. Pepe et al. ( 2013 ) reported population
dynamics of some functional microorganisms involved in composting at different
time interval (Table 12.1 ). The four major classes of bacteria associated in compost
exclusively available for agricultural benefits are firmicutes, β-proteobacteria,
γ-proteobacteria and actinobacteria as stated by Ntougias et al. ( 2004 ). The total ma-
jority of microorganisms involved in composting is summarized in Table 12.2 .
 
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