Fundamental Biochemical and Biotechnological Principles of Biomass Growth and Use 31
In summary, the pressing feedstock challenge asks for comprehensive use of
carbon-containing materials and prioritization on products depending on carbon.
1.4.3 Ecological Considerations
It is widely accepted that the climate change is caused by anthropogenic GHG emis-
sions. However, the public debate often focuses only on CO 2 from fossil-based activities
though agriculture contributes to the whole set of GHG significantly. Therefore,
biomass should be produced and used carefully and as energy- and carbon-efficient
as possible. Efficiency means in this context to transform biomass into energy or
materials with energy and carbon losses as low as possible. This concept analyzes single
production steps and complete utilization chains.
For example, sugar might be extracted from sugarcane. The residual biomass (bagasse)
might first be used to produce second-generation sugar and subsequently be burned
for generating power (what is today the only use). The last step of sugarcane-based
ethanol fermentation is an aqueous solution still containing some organic residues
plus minerals (vinasse), which is considered today a waste and spread on the field as
fertilizer. Before that last utilization step, vinasse could generate biogas, thus yielding
energy from the organic fraction but still retaining the minerals. This concept is called
cascade-use because biomass energy and carbon are utilized in consecutive steps as
completely as possible. The consistent implementation of that concept addresses not
only agricultural biomass but also forestry and marine resources, industrial processing
residues, and even municipal solid and liquid wastes.
Besides reducing agro-related emissions cascade-use also helps to optimize the use of
biomass cultivation areas. This topic is too broad to be discussed here but nevertheless,
in view of the growing world population, it is obvious that land use is critical. This topic
is not only about food production but also about keeping soils fertile, avoid salinization
and erosion, water management, and maintaining biodiversity.
In summary, the modern bio-economy is on the one hand the only alternative
to fossil-based processing with all its implications but on the other does not come
without any environmental burden. To find the most beneficial biomass, its way of
production and later processing in a cascade mode needs careful analysis through life
cycle assessment.
1.4.4 Societal Considerations
1.4.4.1 Food Security
Though agriculture today serves at first food and feed markets, about 870 million people,
which is more than 10% of the world population, are estimated to suffer from hunger.
Mostly regions where agriculture is inefficient because of general under development,
political instability, or climate change are affected but, nevertheless, the fact that hunger
is still in the world raises the question about food security when agriculture feeds not
only people but also industries. This topic has a real global dimension called “indirect
land-use change” (ILUC) when increasing bio-based production demands more biomass
for industrial purposes in one region leads to land-use change (LUC) in another region.
Governments, NGOs, and private parties agree clearly on the priority of agricultural
food production. Industrial feedstock should increasingly be generated from non-food
biomass such as agricultural, forestry, and industrial side streams. Exploiting currently
