51
biohydrogen) and valuable by-products through biochemical processes catalysed by
specific enzymes and microorganisms.
Hence, the main scope of the contribution is to provide insight into the theoretical and practical aspects on the effective biochemical conversion of various organic
substrates via two different biochemical pathways: anaerobic digestion (AD) and
dark fermentation (DF). Both biochemical routes are catalysed by enzymes and
coenzymes which are responsible for the decomposition of organic compounds with
complex structures to compounds with smaller molecules that generate fermentation gases. Anaerobic digestion and dark fermentation processes are very similar in
terms of degradation steps, but each has its own specificity which makes biomass
conversion switching towards biogas or biohydrogen. In this chapter, biomass biochemical conversion processes are presented and analysed, with emphasis on the
operational and process parameters that have to be considered for effective and
economically viable biotechnological conversion. Given that microbial processes
generate both useful products to be used in various applications and some unwanted
chemicals, including hydrogen sulphide, ammonia, siloxanes, volatile organic compounds, etc., which are corrosive or harmful, an important topic discussed in the
chapter concerns the processes of gas stream cleaning and upgrading.
Green chemistry is an economic direction that has got increasing attention in
recent years. By-products resulting from biochemical conversion processes of residual biomass are actually raw materials for many industries. Also, another important
aim of this chapter is to bring attention to the main directions for the use of secondary products as organic fertilizing materials, as well as for the synthesis of intermediates for the chemical industry, composite and adsorbent materials, algal biomass
growth for biofuel industry, etc. Finally, some gaps and issues that need to be prospected in depth are emphasized to make these processes economically and commercially viable. Further exploration on the biomass to biogas and biohydrogen
processing techniques is needed to expand these technologies on a large scale and
replace the available non-renewable energy resources that are exhausted at a much
faster rate than they are generated.
2 Potential Substrates for Biochemical Conversion
to Fuel Gas
Resources that are generally used as substrates in biochemical processes for energy
production include energy crops, agro-industrial residues and by-products, lignocellulosic products, algae and other aquatic plants or organic-loaded wastewaters,
such as municipal sewage sludge, residual waters from zootechnical industry and
animal excreta, etc. [13]. On the other hand, the trend in energy production is
increasingly focusing on waste recovery, which means a broader approach in energy
production is emerging, which does no longer consider singular issues, but a combination of factors sourcing political, environmental, economic and social policies.
Biochemical Conversion of Residual Biomass: An Approach to Fuel Gas and Green…
biohydrogen) and valuable by-products through biochemical processes catalysed by
specific enzymes and microorganisms.
Hence, the main scope of the contribution is to provide insight into the theoretical and practical aspects on the effective biochemical conversion of various organic
substrates via two different biochemical pathways: anaerobic digestion (AD) and
dark fermentation (DF). Both biochemical routes are catalysed by enzymes and
coenzymes which are responsible for the decomposition of organic compounds with
complex structures to compounds with smaller molecules that generate fermentation gases. Anaerobic digestion and dark fermentation processes are very similar in
terms of degradation steps, but each has its own specificity which makes biomass
conversion switching towards biogas or biohydrogen. In this chapter, biomass biochemical conversion processes are presented and analysed, with emphasis on the
operational and process parameters that have to be considered for effective and
economically viable biotechnological conversion. Given that microbial processes
generate both useful products to be used in various applications and some unwanted
chemicals, including hydrogen sulphide, ammonia, siloxanes, volatile organic compounds, etc., which are corrosive or harmful, an important topic discussed in the
chapter concerns the processes of gas stream cleaning and upgrading.
Green chemistry is an economic direction that has got increasing attention in
recent years. By-products resulting from biochemical conversion processes of residual biomass are actually raw materials for many industries. Also, another important
aim of this chapter is to bring attention to the main directions for the use of secondary products as organic fertilizing materials, as well as for the synthesis of intermediates for the chemical industry, composite and adsorbent materials, algal biomass
growth for biofuel industry, etc. Finally, some gaps and issues that need to be prospected in depth are emphasized to make these processes economically and commercially viable. Further exploration on the biomass to biogas and biohydrogen
processing techniques is needed to expand these technologies on a large scale and
replace the available non-renewable energy resources that are exhausted at a much
faster rate than they are generated.
2 Potential Substrates for Biochemical Conversion
to Fuel Gas
Resources that are generally used as substrates in biochemical processes for energy
production include energy crops, agro-industrial residues and by-products, lignocellulosic products, algae and other aquatic plants or organic-loaded wastewaters,
such as municipal sewage sludge, residual waters from zootechnical industry and
animal excreta, etc. [13]. On the other hand, the trend in energy production is
increasingly focusing on waste recovery, which means a broader approach in energy
production is emerging, which does no longer consider singular issues, but a combination of factors sourcing political, environmental, economic and social policies.
Biochemical Conversion of Residual Biomass: An Approach to Fuel Gas and Green…