Using Two Large-scale Seaweed Preparation Of Bio-energy Exploration And Research

Feng Dawei (Marine Pharmacy) Directed by prof. Qin SongFuel ethanol and biogas are both kinds of promising bio-energy. It's important to develop fuel ethanol and biogas to solve the energy crisis and environmental crisis, and it's also meaningful to develop the economy of our country.Studies below were included: saccharification of Laminaria residue(waste of Laminaria industry); saccharification and preliminary ethanol fermentation of Enteromorpha; biogas fermentation of Laminaria; biogas fermentation of Enteromorpha.1, The content of total sugars of Laminaria residue was 52.6%. The polysaccharides of Laminaria residue was composed of 90.9% glucose and a little galactose, mannose and xylose. Laminaria residue was proved to be good material of energy biomass.2, H2SO4 pretreatment of Laminaria residue before enzymatic hydrolysis by cellulase was investigated. When the Laminaria residue was pretreated by 0.6% sulfuric acid that the tempreture was 121℃and the hydrolyzing time was 60 min, the yield of glucose was 187.8 mg/g dry sample after enzymatic hydrolysis by cellulase.3, The enzymatic hydrolysis process of pretreated Laminaria residue by cellulase was optimized. The optimal condition was as following: temperature 45℃, pH 5.2, hydrolyzing time 48h, enzyme loading 16 mg/g dry sample, the yield of glucose after enzymatic hydrolysis was 238.9 mg /g dry sample.4, The content of total sugars of Enteromorpha was 67.2%. The polysaccharides of Enteromorpha was composed of glucose, xylose, glucuronic acid and rhamnose. Glucose and xylose were good material for ethanol fermentation. They accounted for 51% of total sugars of Enteromorpha.5, The processes of acid hydrolysis and enzymatic hydrolysis for fresh Enteromorpha was studied. The process of acid hydrolysis was proved to be much better than enzymatic hydrolysis.6, The process of acid hydrolysis for dry Enteromorpha was studied. H2SO4, HCl, H3PO4 and malelic acid were used in this study. It was showed that H2SO4 is the best of the 4 kinds of acids. When the concentration of the sulfuric acid was 1.8% and the hydrolyzing time was 60 min, the yield of ethanol fermentable sugars (glucose and xylose) was 230.5 mg/g dry sample which accounted for 48.6% of total reducing sugars. It was proved that the dry Enteromorpha was easier to be hydrolyzed by acid than the fresh one.7, The ethanol fermentation process of Enteromorpha was studied. The ethanol yield was low, the content of ethanol in the fermentative liquid was only 0.23%(v/v), The ethanol fermentation process should be optimized in the follow study.8, The best ratio for Laminaria and cattle manure anaerobic co-digestion was 4:1(Laminaria vs cattle manure, w/w). The biogas producing time was 37 days, the total biogas yield was as much as 13600 mL.9, When the inoculation increased to 15 g(dry basis) in the process of Laminaria and cattle manure anaerobic co-digestion, the biogas producing time was 39 days, the total biogas yield was 14630 mL, the TS biogas yield was 152.4 mL/gTS. When the inoculation increased to 21 g(dry basis), the biogas producing time was 36 days, the total biogas yield was 14090 mL, the TS biogas yield was 138.1 mL/gTS. The total biogas yield could be improved by the proper increase of inoculation.10, The best ratio for Enteromorpha and cattle manure anaerobic co-digestion was 4:2(Enteromorpha vs cattle manure, w/w). The biogas producing time was 33 days, the total biogas yield was as much as 6785 mL.11, When the inoculation increased to 7.5 g(dry basis) in the process of Enteromorpha and cattle manure anaerobic co-digestion, the biogas producing time was 38 days, the total biogas yield was 7470 mL, the TS biogas yield was 155.6 mL/gTS. When the inoculation increased to 10.5 g(dry basis), the biogas producing time was also 38 days, the total biogas yield was 7020 mL, the TS biogas yield was 137.6 mL/gTS. The total biogas yield could be improved by the proper increase of inoculation.