Impact of trace element addition on biogas production from food industrial waste - linking process to microbial communities

Abstract

Laboratory-scale reactors treating food industry waste were used to investigate the effects of additions of cobalt (Co), nickel/molybdenum/boron (Ni/Mo/B) and selenium/tungsten (Se/W) on the biogas process and the associated microbial community. The highest methane production (predicted value: 860 mL g(-1) VS) was linked to high Se/W concentrations in combination with a low level of Co. A combination of quantitative real-time PCR of 16S rRNA genes, terminal restriction fragment length polymorphism (T-RFLP) and clone library sequencing was used for the community analysis. The T-RFLP data show a higher diversity for bacteria than for archaea in all the treatments. The most abundant bacterial population (31-55% of the total T-RFLP fragments' intensity) was most closely related to Actinomyces europaeus (94% homology). Two dominant archaeal populations shared 98-99% sequence homology with Methanosarcina siciliae and Methanoculleus bourgensis, respectively. Only limited influence of the trace metal additions was found on the bacterial community composition, with two bacterial populations responding to the addition of a combination of Ni/Mo/B, while the dominant archaeal populations were influenced by the addition of Ni/Mo/B and/or Se/W. The maintenance of methanogenic activity was largely independent of archaeal community composition, suggesting a high degree of functional redundancy in the methanogens of the biogas reactors.

Sulfur K-edge XANES and acid volatile sulfide analyses of changes in chemical speciation of S and Fe during sequential extraction of trace metals in anoxic sludge from biogas reactors

“…Trace metals are important micronutrients for growth and activity of microorganisms in biogas reactors in which organic content of the influent material is biologically converted to methane and carbon dioxide under anaerobic conditions [6][7][8][9][10]. Processes regulating the chemical speciation and bioavailability of trace metals are complex involving dynamic interaction of microorganisms with organic and inorganic compounds [11,12].…”

Effect of a Trace Element Addition Strategy on Volatile Fatty Acid Accumulation in Thermophilic Anaerobic Digestion of Food Waste

“…Increases in VFA corresponded to an increasing total ammonia nitrogen concentration which appeared to become inhibitory at ~2500 mg N l -1 . It has been shown that in mesophilic conditions accumulation of VFA can be prevented by supplementing with selected trace elements [17][18][19][20]. Mesophilic food waste digesters supplemented with trace elements have been shown to operate with good gas production and low VFA concentrations at ammonia concentrations in excess of 6000 mg l -1 , but with a purely hydrogenotrophic methanogenic population; and a mechanism by which trace element addition can prevent VFA accumulation at high ammonia concentrations has been put forward [18].…”

Multiple effects of trace elements on methanogenesis in a two-phase anaerobic membrane bioreactor treating starch wastewater

“…These results showed that iron addition stimulated the methanation activity by enriching critical methanation functional microorganisms. Methanoculleus was reported as saline tolerance and correlated with TE supplementation (Feng et al 2010), which was stimulated by copper and mixed TE group. Methanoculleus was dominated in the recovery group of mixed TE supplementation in which methanation was completely inhibited.…”