Agriculture Reference
In-Depth Information
identified throughout the phase. However, in full scale composting, sequences re-
lated to
Bacillus
sp. were identified only during the later stages of the composting
process. The 16S rRNA gene sequence analysis of thermophilic bacterial isolates
obtained from hot manure compost indicated the presence of four separate clus-
ters belonging to four genera (i)
Geobacillus
, (ii)
Bacillus
, (iii)
Ureibacillus
, and
(iv)
Anureinibacillus
. PCR-RFLP and 16S-ITS-23S region analysis were used for
genetic characterization. Four strains;
Geobacillus thermodenitrificans
,
Bacillus
smithii
,
Ureibacillus suwonensis
and
Anureibacillus thermoaerophilus
were found
to be prevalent and were biochemically characterized. Other
Bacilli
including
B.
coagulans, B. subtilis, G. stearothermophillus
,
G. kaustophilus
,
U. koreensis
,
A.
anureinilyticus
and
Brevibacillus brevis
were also identified (Charbonneau et al.
2012
). The dynamics of the microbial community and its succession on hot chicken
manure compost was characterized using DGGE. The initial abundance of bacte-
rial community shifted from
Acrobacter
sp. to
Bacillus
sp. TP-84 from 5th to 30th
day of the composting. Emergences of sequence related to another
Bacillus
sp.
MSP06G was observed after 15 days of composting. The higher number of
Bacillus
sp. SCSSS08 was exclusively observed during the later phases of the composting.
The study reflected that
Bacillus
spp. are the predominant contributors towards the
hydrolytic degradation of organic matter during the thermophilic phase (He et al.
2013
). Amore et al. (
2013
) reported the predominance of
Bacillus
sp. from indus-
trial waste based compost using 16S rRNA gene identification.
6.6
Enzymes and Enzymatic Processes Associated
with Composting
Composting is a highly complex process that mainly depends on the metabolic ma-
chinery of the microbes and involves different enzymes and enzymatic processes.
The enzymes involved in any composting process vary depending on the compo-
sition of the organic matter in the compost, the physico-chemical conditions that
are prevalent during the composting and the changing dynamics of microbial com-
munity succession. Although a lot of focus has been targeted towards the study of
microbial community structure and succession, only a few studies have focused on
the type, functionality, and progression of the enzymes during composting process.
6.6.1
Proteases
The role and importance of proteases during composting has been acknowledged
by different studies (He et al.
2013
). Proteases have been associated with the nitro-
gen cycle and hydrolysis of proteins and have usually been identified during the
initial phase of the composting process, most likely because of the availability of
oligo-and polypeptides in the initial mixture (Castaldi et al.
2008
). An analysis of
enzymatic activities associated with municipal solid waste compost indicated an
