Corn cob dry

CHAPTER 4: GENERAL CONCLUSIONS

Biomass may encounter considerable dry matter losses due to microbial activity,

depending on the material, the storage conditions and prevention practices. The next generation

of biofuels and the intended bioeconomy will need large amounts of feedstock for producing

food, fuel and fibers in a renewable fashion. Thus it is necessary to understand and quantify the

losses and quality changes that varied feedstock could encounter before being processed.

Although it is important to quantify this parameters, the difficulties associated with

measuring deterioration directly, the technical challenges for relatively small amounts over long

periods and the associated measuring errors poses important challenges for collecting adequate

data.

What appears to be clear is that the amount of dry matter loss can be quite significant.

The microbes’ respiration is directly related to the conditions for their development, i.e., whether

the type material and the environment of storage is supporting their growth. Different types of

cellulosic microorganisms have being identified, with different optimum ranges of moistures,

temperatures, PH, salinity, oxygen levels (aerobic and anaerobic), etc., that directly support their

growth rate. Thereby, the importance of identifying the type of microorganism and the

conditions that prevent their development to consequently improve handling strategies can help

maximize material’s quantity and quality. Needless to say that feedstock, such as agricultural

residues, might need to be stored for prolonged times such as a year or more. Not only biological

decomposition but chemical oxidation will be a concern too. In this sense, extreme conditions
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(biological activity could serve as a starter) could lead to spontaneous combustion and large

number of consequences associated with it.

Corn cobs have been shown to degrade while in storage. Although it is a lignocellulosic

material, in which many cases is claimed to be extremely resilient, with sugars attached with beta

linkage and lignin protecting the fibers, we experience considerable losses in short periods of

time. For the greatest treatment reaching almost 3% in 21 days, and those conditions are yet

likely to be seen in accumulation areas. Although temperature is an important factor, higher

moisture content appeared to be more detrimental, resulting in greater difference of decay for

every percentage in increase (for the range of conditions in this study). Moreover, current storage

practices will likely increase decaying conditions with higher moistures, higher pile

temperature’s, with more degradable materials (chaffs and stover), smaller particle size or with

greater amount of inoculum (for example with soil contamination) that might ramp up the rates

of deterioration. Further studies with other materials, and conditions listed above should follow

this preliminary study to correctly assess storage conditions and consequently improve handling

strategies.

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