Biorefineries using waste – production of energy and chemicals from biomasses by micro-organisms - Biomass as Energy Source: Resources, Systems and Applications - page 256

and byproduct and waste piles constituting a high number of raw material mixtures and process
alternatives. These various processes and their products could be then manufactured in a flexible
manner according to the market demand, for example. Such a “field idea” of biorefinery con-
struction was presented and later put into practice successfully within the framework of BECON
2004 program in Iowa, USA. There the agricultural wastes were and have been in the scope of
industrial revolution (Iowa Energy Center, 2013).

13.13 CONCLUSIONS

Modern applications of biotechnological industries are in many countries being directed towards
gradual complementation or replacement of the petrochemical industries. This is a consequence
of diminishing resources worldwide and potentially limited access to the sources. On the other
hand, biomass surplus and wastes are available widely. The process should be developed further
into the direction of increased sustainability, productivity and integration. The flexibility of the
microbial processes makes them increasingly attractive. Biocatalysis with microbes and their
enzymes is also an energetically feasible way to build up production of fuels and chemicals for
the future needs. Microbial metabolism offer huge potential for development in this respect. When
the capabilities of several microbes are combined in the case of mixed cultures, increasingly better
results are to be achieved. In order to have these results actualized as industrial applications, also
the reactor design and downstream processing have to develop hand in hand with the process
microbiology.

QUESTIONS FOR DISCUSSION

• What is the important aspect of biocatalysis in the biotechnical processes from the energetic

point of view?

• Why could the mixed microbial cultures often replace genetic engineering in the biorefinery

process design?

• Mention the benefits of using thermophilic organisms in the production of e.g. ethanol.

• Which one of the following claims is untrue? The flexibility of the biotechnological approach

in comparison with chemical engineering is based on:
◦ producing fewer products from mixed substrates,

◦ the possibility of using alternative raw materials in the same production unit,

◦ switching the bioreactor into variable processes if needed, or

◦ small-scale solutions with local raw materials.

• Efforts to improve the bioprocess can be directed towards selecting the production strain,

studying its physiology, bioreactor design, and integrated downstream processing. Describe
these alternatives in the commercialization of biobutanol production in an anaerobic sludge
reactor.
• Give examples of lignocellulosic biomasses and introduce the problems in their effective
utilization.
• Why, when and how should combustion be replaced by bioprocess applications?
• Could the biorefinery field replace the oil refineries, and eventually or step-by-step the
petrochemical industries?
• Why could bioprocesses often be considered as an ecologically sustainable solution?

REFERENCES

Alén, R.: Structure and chemical composition of wood. In: P. Stenius (ed.): Forest products chemistry . Fapet
Oy, Helsinki, Finland, 2000, pp. 11-57.