Enrichment of thermophilic and mesophilic microbial consortia for efficient degradation of corn stalk

Six different environmental samples were applied to enrich microbial consortia for efficient degradation of corn stalk,under the thermophilic and mesophilic conditions.The consortium obtained from anaerobic digested sludge under thermophilic condition(TC-Y)had the highest lignocellulose-degrading activity.The CO_2yield was 246.73 m L/g VS in23 days,meanwhile,the maximum CO_2production rate was 15.48 mL/(CO_2·d),which was28.75%and 52.27%higher than that under mesophilic condition,respectively.The peak value of cellulase activity reached 0.105 U/mL,which was at least 34.61%higher than the other groups.In addition,49.5%of corn stalk was degraded in 20 days,moreover,the degradation ratio of cellulose,hemicellulose and lignin can reach 52.76%,62.45%and42.23%,respectively.Microbial consortium structure analysis indicated that the TC-Y contained the phylum of Gemmatimonadetes,Acidobacteria,Chloroflexi,Planctomycetes,Firmicutes,and Proteobacteria.Furthermore,the Pseudoxanthomonas belonging to GammaProteobacteria might be the key bacterial group for the lignocellulose degradation.These results indicated the capability of degrading un-pretreated corn stalk and the potential for further investigation and application of TC-Y.

Efficient promotion of methane hydrate formation and elimination of foam generation using fluorinated surfactants

Methane hydrate preparation is an effective method to store and transport methane.In promoters to facilitate methane hydrate formation,homogeneous surfactant solutions,sodium dodecyl sulfate(SDS)in particular,are more favorable than heterogeneous particles,thanks to their faster reaction rate,more storage capacity,and higher stability.Foaming,however,could not be avoided during hydrate dissociation with the presence of SDS.This paper investigated the ability of five fluorinated surfactants:potassium perfluorobutane sulfonate(PBS),potassium perfluorohexyl sulfonate(PHS),potassium perfluorooctane sulfonate(POS),ammonium perfluorooctane sulfonate(AOS),and tetraethylammonium perfluorooctyl sulfonate(TOS)to promote methane hydrate formation.It was found that both PBS and PHS achieve a storage capacity of 150(V/V,the volume of methane that can be stored by one volume of water)within 30 min,more than that of SDS.Cationic ions and the carbon chain length were then discussed on their effects during the formation.It was concluded that PBS,PHS,and POS produced no foam during hydrate dissociation,making them promising promoters in large-scale application.