瘤胃液用于玉米秸秆产酸的影响因素

Influencing factor of VFA production with corn straw inoculated with rumen fluid

以瘤胃液为接种物对秸秆进行批式实验,研究了发酵时间、发酵温度与接种比对秸秆发酵产酸的影响。发酵3 d后,发酵液的pH、VFA浓度、SCOD浓度与产气量基本达到稳定值,分别为6.66±0.02、(6 321±45)mg·L^(-1)、(10 523±273)mg·L^(-1)与(1 351±41)m L,反应基本结束;相比其他温度,在39℃时,VS转化率与VFA产率达到最大值,分别为(46.7±2.3)%与(291±4)mg·g-1(以VS计),发酵液的最终pH也达到最小值7.19±0.03;随着接种比从0.47减小到0.09,VFA产量从(5 704±46)mg·L^(-1)升高到(9 633±143)mg·L^(-1),但是VS转化率、最终pH与VFA产率分别从(58.5±0.8)%、6.54±0.00与(603±5)mg·L^(-1)下降到(26.6±3.4)%、5.44±0.04与(204±3)mg·L^(-1),其中0.16为极限接种比,当接种比低于该值时,总产气量不再增加。

This study investigates the effect of fermentation time,temperature,and inoculum ratio on VFA production on maize straw inoculated with rumen fluid under batch conditions. Final pH,VFA concentration,SCOD concentration,and gas yield became almost stable after three days of fermentation,which accounted for 6. 66 ±0. 02,（ 6 321 ± 45） mg·L^（-1）,（ 10 523 ± 273） mg·L^（-1）,and（ 1 351 ± 41） m L,respectively,at which point,the reaction was almost complete. Compared with other treatments in the temperature experiment,39 ℃ was the optimal temperature for straw degradation and VFA production with a VS conversion rate of（ 46. 7 ± 2. 3） % and a VFA yield of（ 291 ± 4） mg·g- 1（ calculated by VS）. Meanwhile,the final pH（ 7. 19 ± 0. 03） in the fermentation system was lowest at 39 ℃. Although VFA production rate increased from（ 5 704 ± 46） to（ 9 633 ± 143）mg·L^（-1）,VS conversion rate,final pH,and VFA yield decreased from（ 58. 5 ± 0. 8） %,6. 54 ± 0. 00,and（ 603 ± 5） mg·L^（-1）to（ 26. 6 ± 3. 4） %,5. 44 ± 0. 04,and（ 204 ± 3） mg·L^（-1）,respectively,as the inoculum ratio decreased from 0. 47 to 0. 09. Gas yield did not increase when the inoculum ratio was less than 0. 16;therefore,0. 16 was the limiting inoculum ratio.