How Barley Fermentation Produces Gas and Greenhouse Gases with Helpful Bacteria

Jim Crocker
10th June, 2024

How Barley Fermentation Produces Gas and Greenhouse Gases with Helpful Bacteria

Image Source: Natural Science News, 2024

Key Findings

  • The study took place in Inner Mongolia and focused on greenhouse gas (GHG) production during barley silage fermentation
  • Adding lactic acid bacterial (LAB) additives to barley silage significantly reduced GHG emissions compared to untreated silage
  • LAB additives also improved fermentation quality and reduced weight loss during the initial stages of fermentation
Greenhouse gases (GHGs) such as carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) are significant contributors to climate change. Their production during the fermentation of silages, particularly barley silage, has not been extensively studied. In a recent study by the Inner Mongolia Academy of Agriculture and Animal Husbandry Science[1], researchers sought to understand the dynamics of GHG production in barley silage and assess methods to mitigate these emissions. The study involved harvesting barley at the milk stage and ensiling it without additives (CK) or with two commercial lactic acid bacterial (LAB) additives (L1 or L2). Over a period of 90 days, the researchers measured gas and GHG production, fermentation quality, weight loss, and bacterial communities at various intervals (days 0, 1, 3, 6, 15, 35, and 90). Results showed that gas and GHG production increased rapidly in the CK group during the first three days and in the L1 and L2 groups during the first day, before decreasing. The CK group exhibited higher levels of gas and GHG production compared to L1 and L2 from day 1 to day 35, with peak production observed at day 6 for CK and day 3 for L1 and L2. This indicates that LAB additives can significantly reduce GHG emissions during the initial stages of fermentation. The study found that gas and GHG production were positively correlated with the presence of Coliforms and the abundances of Enterobacter, Klebsiella, and Atlantibacter from day 0 to day 6. Conversely, these emissions were negatively correlated with the abundances of beneficial bacteria such as Lentilactobacillus, Lactiplantibacillus, and Lacticaseibacillus from day 1 to day 35. This suggests that certain bacterial communities play a crucial role in the accumulation and reduction of GHGs during silage fermentation. Interestingly, the study aligns with earlier findings on the impact of LAB on silage fermentation. For instance, previous research demonstrated that Lactobacillus plantarum (LP) could reduce CO2 production and weight loss in stylo and rice straw silages by altering bacterial communities[2]. Similarly, the current study showed that LAB additives like L1 and L2 could mitigate GHG emissions by influencing the bacterial composition in barley silage. Furthermore, the study observed that Lentilactobacillus dominated the bacterial communities in the L1 and L2 groups from day 35 to day 90. This dominance was associated with increased pH and acetic acid (AA) levels and decreased lactic acid levels after day 15, indicating a deterioration in fermentation quality during the late fermentation phase. These findings are consistent with earlier research that highlighted the role of lactic acid bacteria in improving silage quality and reducing fermentation losses[3]. The study also found that fermentation weight loss (FWL) was positively correlated with gas and GHG production from day 1 to day 35. This suggests that the GHGs generated during silage fermentation contribute to the overall loss of silage mass, highlighting the importance of minimizing GHG emissions to preserve silage quality. In summary, the research by the Inner Mongolia Academy of Agriculture and Animal Husbandry Science provides valuable insights into the dynamics of GHG production during barley silage fermentation. The use of LAB additives like L1 and L2 can effectively reduce GHG emissions by altering bacterial communities, thereby improving fermentation quality and reducing weight loss. These findings build on previous studies that demonstrated the benefits of LAB in silage fermentation[2][3], offering a promising approach to mitigate GHG emissions in agricultural practices.



Main Study

1) Dynamics of gas and greenhouse gases production during fermentation of barley silage with lactic acid bacteria

Published 9th June, 2024

Related Studies

2) Altering bacterial community: A possible way of lactic acid bacteria inoculants reducing CO2 production and nutrient loss during fermentation.

3) Influence of lactobacillus spp. from An inoculant and of weissella and leuconostoc spp. from forage crops on silage fermentation.

Journal: Applied and environmental microbiology, Issue: Vol 64, Issue 8, Aug 1998

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