This Thai experiment used spent mushroom substrate to pretreat rice straw at 3:1 and 5:1 ratios, then co-digested the 5:1 material with cow manure anaerobically. Hemicellulose decreased after pretreatment, but biogas production did not significantly differ among the three digestion ratios.
Key findings
- Untreated straw contained 33.76% cellulose, 34.90% hemicellulose, and 21.94% lignin; 3:1 material had 35.50%, 16.29%, and 28.30%; 5:1 had 37.36%, 18.11%, and 25.77%. Despite lower hemicellulose, gas production did not differ (F=0.40, p>0.05).
Why this matters globally
Combining rice straw, spent mushroom substrate, and manure fits rural circular-economy goals, but viability depends on methane fraction, net energy, retention time, and digestate, not total gas volume alone.
Thai researcher contribution
The Rajabhat Rajanagarindra University team tested wastes relevant to Thai agriculture and transparently reported a null gas-production result, helping avoid assumptions that pretreatment must improve yield.
Limitations to consider
Only two replicates provide low power. Methane fraction, cumulative yield per VS/TS, retention time, temperature, pH, inoculum, and uncertainty are not stated. Proportional composition shifts may reflect loss of other fractions, and p>0.05 does not prove equivalence.