Comparison of various microbial inocula for the efficient anaerobic digestion of Laminaria hyperborea

BMC Biotechnology

Alastair D Sutherland¹  Joao C Varela¹ 

[1] Centre of Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal

关键词: Methane;    Laminaria hyperborea;    Anaerobic digestion;    Microbial inoculum;    Seaweed;   

Others  :  834949
DOI  :  10.1186/1472-6750-14-7

 received in 2013-06-03, accepted in 2013-10-23,  发布年份 2014

【 摘 要 】

Background

The hydrolysis of seaweed polysaccharides is the rate limiting step in anaerobic digestion (AD) of seaweeds. Seven different microbial inocula and a mixture of these (inoculum 8) were therefore compared in triplicate, each grown over four weeks in static culture for the ability to degrade Laminaria hyperborea seaweed and produce methane through AD.

Results

All the inocula could degrade L. hyperborea and produce methane to some extent. However, an inoculum of slurry from a human sewage anaerobic digester, one of rumen contents from seaweed-eating North Ronaldsay sheep and inoculum 8 used most seaweed volatile solids (VS) (means ranged between 59 and 68% used), suggesting that these each had efficient seaweed polysaccharide digesting bacteria. The human sewage inoculum, an inoculum of anaerobic marine mud mixed with rotting seaweed and inoculum 8 all developed to give higher volumes of methane (means between 41 and 62.5 ml g^-1 of seaweed VS by week four) ,compared to other inocula (means between 3.5 and 27.5 ml g^-1 VS). Inoculum 8 also gave the highest acetate production (6.5 mmol g^-1 VS) in a single-stage fermenter AD system and produced most methane (8.4 mL mmol acetate^-1) in phase II of a two-stage AD system.

Conclusions

Overall inoculum 8 was found to be the most efficient inoculum for AD of seaweed. The study therefore showed that selection and inclusion of efficient polysaccharide hydrolysing bacteria and methanogenic archaea in an inoculum offer increased methane productivity in AD of L. hyperborea. This inoculum will now being tested in larger scale (10L) continuously stirred reactors optimised for feed rate and retention time to determine maximum methane production under single-stage and two-stage AD systems.

【 授权许可】

   
2014 Sutherland and Varela; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

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