Research Of Anaerobic Fermentation Hydrogen Production Using Hydrolysate Of Marine Macroalgae

Marine macro-algae were known as the third generation of biomass,now more and more researchers focus on the resource utilization.In this study,we take the macro-algae Laminaria japonica as material to make hydrolysate by pretreatment methods,including physical and chemical methods,and research the properties of anaerobic fermentation hydrogen production using hydrolysate of Laminaria japonica.We use both thermal and acid pretreatment method to make hydrolysate of Laminaria japonica.The result show that the thermal pretreatment method?121? 20 min?with the high effective hydrolysate rate of total sugar is 23.88%and the acid pretreatment method?1.0%H2SO4?with the high effective hydrolysate rate of reducing sugar is 30.84%.The monosaccharide composition in the hydrolysate of Laminaria japonica using different pretreatments are mainly include:Fucose,Mannose,Galactose and Galacturonic acid.Under the different pretreatment methods,the monosaccharide content in the hydrolysate of Laminaria japonica were different obviously,thermal pretreatment?121?,20 min?with the highest content of Galacturonic acid is 9.50%,and highest content of Fucose in the thermal pretreatment?100?,10 min?,acid?1.5%HCI?,acid?1.0%H2SO4?are 11.91%.1 1.48%and 30.1 1%respectively.Collect the intertidal sludge from marine of Tianjin,using the hydrolysate of Laminaria japonica for anaerobic bacteria fermentation to enhance the mixed bacteria.Using the high-throughput sequencing technologies to analysis constitute of mixed hydrogen bacteria.Result show that the mixed bacteria in the control group can be annotated 19 Phylum,31 Class,71 Order,118 Family and 159 Genus.There exist total advantage bacterium group in the thermal and acid pretreatment hydrolysate of Laminaria japonica.They are mainly focused on Firmicutes and Proteobacteria;Clotridia and Bacilli;Clostridiales and Bacillales;Ruminococcaceae and Clostridiaceae₁;Clostridium_sensu_stricto₁.In addition,the mixed bacteria with the highest diversity is in the hydrolysate of HCl pretreated Laminaria japonica,and the Shannon index is 5.253.we detect the hydrogen production of mixed bacteria which was cultured in the hydrolysate of Laminaria japonica using different pretreatment.Result show that the mixed bacteria with the highest htdrogen production?825.68 ml/L?which was cultured in the hydrosate of HCl pretreated Laminaria japonica.It was increased by 61.1 1%compared with the control group.We use hydrolysate of Laminaria japonica as only medium to train the hydrogen producing strain.Screening one hydrogen producing strain and named as Clostridium sp.WANY51?Registration number:KY197470?.The strain was gram positive,with the size of 8.19umx l.45um.Strain Clostridium WANY51 metabolic butyric acid,butyl alcohol and acetic acid at the end of anaerobic fermentation.Strain Clostridium sp.WANY51 using hydrolysate of Laminaria japonica?volume ratio is 80%?has the highest efficiency of hydrogen production,is 990.50 ml/L.Strain Clostridium sp.WANY51 has the highest efficiency of hydrogen production,is 987.07 ml/L when was cultured in the initial pH7.0 of hydrolysate of Laminaria japonica.Strain Clostridium sp.WANY51 can able to take advantage of marine macro-algae and producing hydrogen,this will provide new experimental evidence on two facts:Microbial hydrogen production and Recycling use of marine macroalgae.