Agriculture Reference
In-Depth Information
acidification during ensiling and control the fermentation pattern to avoid undesirable growth
of spoilage microorganisms such as butyric acid-producing clostridia and enterobacteria some
chemical additives (e.g., formic acid, acetic acid and sulfuric acid) and lactic acid bacteria
inoculants are often added to the silage [7]. The duration of ensiling varies with the nature of
the forage being ensiled, particularly, the initial concentration of fermentable sugars and the
population of lactic acid bacteria.
One of the challenges of sugar beet shreds utilization for animal feeding is their
stabilization during storage. Ensiling of wet and partially dry sugar beet sheds is an
alternative to dry storage of sugar beet shreds. During ensiling of sugar beet shreds the most
distinguished change is fermentation mainly of water soluble carbohydrates into short chain
organic acids and alcohols. The most important product of ensiling sugar beet shreds is lactic
acid which is formed as a result of lactobacili in the bulk of feed material [2].
The main goal of ensiling sugar beet shreds is to preserve their nutrition value and to
minimize qualitative and quantitative loss as much as possible. It is neccessary to emphasize
that the losses are inevetable in both dry matter and feed quality because they come out as
result of biochemical reactions as well as from the processes of tissue desintegration and
consequent water release [2].
Recently ensiling as microbial conversion of sugar beet shreds has been investigated as a
novel storage method to supply stable biomass for year-round biorafinery industries [7].
Regarding this, the effects of ensiling on storage and subsequent enzymatic hydrolysis were
studied. It was found that acetic acid inoculants improved sugar beet preservation and
prevention of cellulose and hemicellulose loss. Moreover, ensiling process significantly
improved enzymatic digestibility of sugar beet shreds so obtained results suggest that this
microbial conversion may also be a promising pretreatment technology for their
bioconversion to value-added products of biotechnology.
2.2. Protein Enrichment
Usage of wastes from agriculture and food industry for animal feeding is constrained to
some extent by their very low content of protein, vitamin, oil and other nutrient and limited
digestibility and palatability to ruminants. However, they may be applied for animal nutrition
following protein enrichment by using a variety of micro and macro fungi and bacteria.
So, if appropriate technologies will be developed for their valorization by protein
enrichment these wastes can represent valuable biomass and potential solutions to problems
of animal nutrition and world wide supply of protein and calories. Applied technologies
would need to consider and to be adjusted to characteristics of individual wastes as well as to
environment in which they are generated, reprocessed and used [14].
Generally, technologies available for protein enrichment of agricultural and food industry
wastes include solid substrate cultivation, ensiling and high solid or slurry processes but the
main efforts in this direction have emphasized the use of solid substrate cultivation. The
choice of microbial type to grow on lignocellulosic wastes depends to a large extent on the
desired end product, and on whether or not a pretreatment step is included or needed in the
cultivation process. In adition, protein enrichment of agro-food waste may be accompanied by
the microbial production of valuable biochemicals such as food/feed grade enzymes [15] and
organic acid [16]. In most cases the production of protein enriched lignocellulosic waste has
