自然干燥甜高粱茎秆长期贮藏及乙醇发酵研究

Air-dried sweet sorghum stalk for long-term storage and ethanol fermentation

为了延长甜高粱乙醇生产原料供应时间,将甜高粱茎秆自然干燥后用于长期贮藏。分别考察干燥和长期贮藏过程糖分变化,结果显示,自然干燥过程中,茎秆的含水率(干基)由80%降低至18%时,总糖损失率为3.85%;不同含水率的茎秆经6个月长期贮藏,含水率为22%以下茎秆中的总糖和还原糖基本保持不变。表明自然干燥过程使总糖损失较小,22%可作为甜高粱茎秆干燥贮藏的"安全含水率"。通过考察干燥的茎秆乙醇发酵的可行性,结果表明,固态发酵24h即可达到终点,基质中的乙醇质量分数可以达67.06mg/g(干基),发酵过程基本正常。通过该研究,表明自然干燥可作为甜高粱茎秆长期贮藏的一种较为有效的加工方式,可为解决甜高粱乙醇周年生产的原料供应问题提供一定技术参考。

The air-dried sweet sorghum stalk was employed for a long-term storage to prolong the raw material supply for ethanol production. The change of sugar content in the stalk was investigated in the drying and the storage process, respectively. Results indicated that the total sugar loss during the drying process was 4.58%, when the moisture of fresh stalk decreased from 80% to 18%. In the subsequent 6 months storage duration, the total sugar and reducing sugar in the dried stalk almost kept no obvious decrease when the stalk moisture was lower than 22%. The ‘safe moisture’ for dried sweet sorghum long-term storage could be thereby regarded as 22%. After 6 months storage, the dried stalk was rehydrated for fermentation to check the fermentability. Results showed fermentation could be rapidly completed in 24 h and ethanol concentration in substrate could reach 67.06 mg/g （wet basis）. There were no obvious inhibitions in the fermentation process. According to the results above, it was an effective way to store sweet sorghum stalk for a long time by air-drying stalk. This work could give a potential solution to the shortage of raw material supply in the year-round ethanol production from sweet sorghum stalk.