PLFAs of the microbial communities in composting mixtures of agro-industry sludge with different proportions of household waste

Abstract

Phospholipid fatty acids (PLFAs) were analysed at different time periods during composting of two waste mixtures rich in fats, M1 (22%) and M2 (39%), with the aim of monitoring changes in microbial community structure. The two mixtures consisted of a sludge sample collected from a vegetable oil refinery effluent treatment plant combined with household wastes. The PLFA profiles of both mixtures revealed that, at the start of the process, fungi and Gram-negative bacteria (GÀ) were more abundant in M2 than in M1. During the thermophilic phase, branched PLFA (i15:0, a15:0, i16:0, and i17:0) markers of Gram-positive bacteria (Gþ), became more abundant in M1, while G-bacteria were predominant in M2. The PLFA profiles in M1 representing non-specific, Gþ and GÀ bacteria as well as fungi decreased during the cooling phase (maturation) while an increase was recorded in M2, which was richer in fats. The ShannoneWeaver diversity index (Ish) showed a greater increase during M1 composting (from 0.69 to 1.05), mainly for Gþ bacteria and GÀ bacteria, than in M2 composting (from 0.79 to 0.84). Principal components and cluster analyses revealed a succession of different communities during composting, which varied from fungi and GÀ bacteria to Gþ and thermophilic and thermotolerant GÀ bacteria. The end of composting was characterized by a reduction of all these microbial entities, especially for M1, except actinomycetes, which are associated with compost stability.

Seafood-Processing Sludge Composting: Changes to Microbial Communities and Physico-Chemical Parameters of Static Treatment versus for Turning during the Maturation Stage

“…Nonetheless, a decrease in temperature did not produce an observable increase in how abundant fungi were; both treatments, however, were characterized by the fungal biomass being predominant, particularly in the case of static treatment, throughout the entire process. Amir et al [44] found that fungi are more present in wastes with a high level of fatty acids. Likewise, Villar et al [13] suggested that the influence the initial material, in this case lipid in nature and pH, has on the maturation phase is reflected by microbial diversity; this means that although the waste undergoes significant degradation during the composting process, the properties of the starting material determine the dominant microbial groups throughout the maturation stage.…”

Valorisation Agricole D’un Compost Produit À Partir Du Compostage En Cuve Des Déchets Municipaux

“…Le compostage est un processus aérobie de dégradation des composés organiques par l'action successive des micro-organismes (bactéries et champignons) dont la concentration peut atteindre des millions par gramme de compost (Barje et al, 2008, Jouraiphy, 2007, Amir, 2005Amir et al, 2010) ; leur évolution est en fonction des stades de compostage avec un profil défini, en fonction des espèces, à la nature et la structure des substrats et aussi liée principalement aux variations des paramètres physico-chimiques (Rosenzweig et al, 1980). Au cours du processus de compostage réalisé, la flore microbienne varie considérablement ( fig.9).…”

Identification and assay of microbial fatty acids during co-composting of active sewage sludge with palm waste by TMAH-thermochemolysis coupled with GC-MS

“…The iso and anteiso-(i, a) in C15:0; C16:0 and C17:0 are commonly used as signature fatty acids for bacteria, especially Gram-positive bacteria, [4,13] as well as C15:0, C17:0 which indicate non-specific bacteria; and unsaturated fatty acids C18:1ω7c, C18:1ω9c indicate a bacterial origin especially Gram-negative. [15,16] The levels of total lipid and of total FAMEs during the two co-composting trials are plotted in Figure 1(a) and 1(b).…”

“…[10] This fall in the level of extractable lipid supports the work of numerous authors studying waste composting. [13,17] It can be attributed to their breakdown by the intense microbial activity, nevertheless, it has been shown [18] that lipids which are not directly extractable are less biodegradable, for instance those chemically bonded to organic matter or adsorbed by the mineral matrix. After the decrease in extractible lipids, significant increases in FAMEs occurred during co-composting in both trials: FAMEs rose by 8.44-33.30% and 10.76-43.40% for mixtures A and B, respectively.…”

“…According to Amir et al, [13,26] Parkes, [34] and Cahyani et al [35] iso-and anteiso-branched fatty acids (i and a) C15:0, C16:0 and C17:0 are considered to be an indicators of Gram-positive bacterial growth during the stabilisation phase of composting. As already reported by Steger et al, [4] Amir et al [26]; in the present study iC15:0 (Figure 2(g) and 2(h)) rose during the thermophilic phase, when the temperature was high (over 65 • C) which indicates that branched fatty acid i−C15:0, is characteristic of thermophilic microorganisms, especially bacteria during co-composting.…”