Page 536 - Refining Biomass Residues for Sustainable Energy and Bioproducts

488 Refining Biomass Residues for Sustainable Energy and Bioproducts

22.2.5 Seagrass

Seagrass are different from seaweed because of the presence of roots, stems, and
leaves and considered as vascular plants. It is a main candidate of precious flora of
marine habitat because of the characteristics of storage of carbon, development in
quality of water, reservoir of food as well as considered as a biological indicator
(Fourqurean et al., 2012). Seagrasses develop equal, intertidal, and subtidal in all
the conditions. It is a unique and submerged flowering plant that grows in all the
continents. Widespread seagrass region are frequently known to as seagrass beds or
meadows, varied from a few square meters to hundreds of square kilometers, which
otherwise act as binding sediments and also it will provide shield from erosion
(Cullen-Unsworth and Unsworth, 2016).

22.3 Marine waste disintergation techniques

Organic wastes used for biogas production by means of mono- and codigestion
technique have been broadly described. For enhancing biogas production, differ-
ent pretreatment processes such as (1) mechanical, (2) thermal, (3) chemical, and
(4) biological treatments have been reported (Zhen et al., 2014; Banu and
Kavitha 2017; Banu et al., 2017; Kannah et al., 2018). The majority of the
research related to disintegration of natural wastes into biogas was committed to
mechanical, thermal, and chemical techniques achieved up to 33%, 24%, and
21%, respectively. The principles of pretreatment methods are to (1) while stor-
age and handling, decrease CO 2 emission due to the carbon loss; (2) progress the
exterior characteristics for the admittance of microorganisms; (3) decrease the
gathering of volatile fatty acids (VFAs) on premature phase; and (4) alter the bio-
logical characteristics for the easy access of microorganism (Yeneneh et al.,
2013). Table 22.2 shows various pretreatment on marine macroalgae and their
effect on biofuel production.

22.3.1 Mechanical pretreatment

Mechanical pretreatment helps to decrease the organic particles, without producing
any inhibitory products and produce the biogas by enhancing the physical properties
such as surface area (Devi et al., 2014; Kavitha et al., 2016, 2018; Gayathri et al.,
2015). The main disadvantage of this mechanical pretreatment is, it demands more
energy for the process. Due to this, progress of milling techniques demonstrate so
as to exhibit the most suitable process of dry milling than the wet milling because
of its advanced pulverization characteristics through negligible energy utilization
(Weiland, 2010). In addition to that, it assists the disintegration in less retention
time. Moreover, screw press, lysis-centrifugation are the techniques otherwise
employed to develop the characteristics of waste.