Page 544 - Refining Biomass Residues for Sustainable Energy and Bioproducts

Bioconversion of marine waste biomass for biofuel and value-added products recovery 493

biological treatment are a difficult process. However, enzymes produced from these
microorganism can be used for the digestion process is considered as a cost-
effective method (Yin et al., 2016).

22.4 Marine waste processed for bio-based product

Alternative energy sources such as biorenewable, hydro, solar, wind, geothermal
have both advantages and disadvantages. Bio-based products possibly will be a dis-
tinct one as polymeric material, which can be derivative of various biomasses.
Different types of marine waste are converted into bioenergy products such as bio-
methane, biohydrogen, bioethanol, and biodiesel (Vavilin and Angelidaki, 2005).

22.4.1 Bioenergy products

Renewable resources such as solar, wind, tidal, and biomass have been used for the
generation of energy because of the deficiency of fossil combustibles, which other-
wise cause various ecological troubles. Biogas is derived from the biomass, and this
is called a renewable energy, and currently, biogas-producing industries are mainly
worked on global energy crops. For the growth of these types of crops, considerable
land, freshwater, and fertilizer are needed. Now the novel invention of biofuels
acquired from marine biomass will reduce the anxiety of the current state of affairs.
However, in the coastal regions around the world affected by the formation of
extensive algal blooms and hypertrophication, the extensive growth of algae leads
to the threat to marine ecosystem (Gregeby and Welander, 2012). This unwanted
biomass utilized as a substrate to produce biofuels and also considered as a substi-
tute for energy crops. These marine biomasses possibly will be transformed into a
range of energy forms together with heat, steam, electricity, hydrogen, ethanol,
methanol, and methane (Hughes et al., 2012). Fig. 22.2 shows marine waste pre-
treatment and its bioenergy recovery.

22.4.1.1 Biomethane via anaerobic digestion
AD is one of the biological processes where the organic components can be decom-
posed and converted into useful biogas in oxygen-free environment. AD involves
various subreactions. The biogas produced during the AD process primarily consists
50% 75% of methane, 25% 45% of carbon dioxide, 2% of oxygen, 2% of nitro-
gen, 1% of hydrogen sulfide, and 1% of ammonia (Matsui et al., 2006). The novel
technology of AD has been profitably executed in the management of wastes from
agricultural, food, and marine wastes because of the potential of reducing chemical
oxygen demand and biological oxygen demand from different waste with the gener-
ation of renewable energy (Zhang et al., 2014). AD uses the association of microor-
ganism to decompose the organic waste. It is the synergistic process and can be
categorized by metabolic pathway sequence. Most important steps of AD are hydro-
lysis, acidogenesis, acetogenesis, and methanogenesis (Xu et al., 2015). During the