Page 512 - Refining Biomass Residues for Sustainable Energy and Bioproducts

468 Refining Biomass Residues for Sustainable Energy and Bioproducts

21.5.1 Biofuels

The world’s energy demand lingers to increase and major resources such as fossil
fuel are exhausted; there is an increasing attraction on maritime resources as an
alternative renewable source for fuels and chemical production. In 2016 the global
market for the production and wholesale pricing of ethanol and biodiesel was sized
at B101 billion USD, further, by 2023 the market is expected to grow B133 billion
USD. According to Zion Market Research report, the global biofuel market is antic-
ipated to grow at 4.5% compound annual growth rate (CAGR) between 2017 and
2022. Marine algae including macroalgae and microalgae are the potential alterna-
tive renewable biomass feedstock for biofuel production for their high lipid content
and biomass value. Seaweed hydrolysis effectively converts polysaccharides
into simple sugars, which is utilized by natural microbes to produce ethanol
(Diep et al., 2012). The different seaweeds used in the production of biofuels are
Laminaria japonica, Gelidium amansii, Sargassum fulvellum, Ulva lactuca, and
Ulva pertusa. Marine yeast is also another biorefinery used in bioethanol, pharma-
ceutical, and enzyme production fields. Large-scale production of biofuels using
edible oils may cause a disparity in global food supply and market demand.
Therefore, nonedible oils or oils from waste were suggested as an alternative oil
resource for biofuel production. The biofuel production from marine resources has
more attraction for low-cost production at large scale, that is, production economics
is the bottleneck for the commercialization of the product in the market (Jiang
et al., 2016; Milledge and Harvey, 2016). Synthetic biology and advanced meta-
bolic engineering approaches offer new opportunities to increase the success rate of
marine-derived biofuels in the future (Wei et al., 2013).

21.5.2 Enzymes
The global enzymes market is registering a compound annual growth rate of 5.7%
from 2018 to 2024. In general, enzymes are isolated from plants, animals, and
microbial sources. In terms of availability and cost the microbial source was the
potential candidate for enzyme production. Recently, researchers have isolated a
variety of enzymes with special activities from marine bacteria, actinomycetes,
fungi, and other marine microorganisms (Trincone, 2017). Marine enzymes, such as
amylases, proteases, lipases, agarases, chitinases, carboxymethylcelluloses, kerati-
nases, xylanases, peroxidase, and tyrosinases, are used in food and pharma industry
and also wastewater treatment (Zhang and Kim, 2010). Bacillus sp., Pseudoalteromonas
sp., Marinomonas sp., and Sulfitobacter sp. are the major sources of the protease.
Several microbes produce lipases; however, the foremost lipase producers are
Aeromonas sp., Pseudoalteromonas sp., Psychrobacter sp., Photobacterium lipolyticum,
Pseudomonas sp. strain B11-1, Pseudomonas sp. 7323, and Bacillus sp. S14. The
microorganisms are capable of degrading chitin and chitosan such as Aspergillus,
Penicillium, Rhizopus, Myxobacter, Sporocytophaga, Bacillus, Enterobacter,
Klebsiella, Pseudomonas, Serratia, Chromobacterium, Clostridium, Flavobacterium,
Arthrobacter, Streptomyces, Vibrio fluvialis, Vibrio parahaemolyticus, Vibrio mimicus,