Page 282 - Refining Biomass Residues for Sustainable Energy and Bioproducts

250 Refining Biomass Residues for Sustainable Energy and Bioproducts

HB1. Batch fermentation yielded 24.92 g/L of PGA using corncob fiber hydrolyzate
as a substrate.

11.2.3 Enzymes
Agroresidues serve as suitable substrates for the production of different industrial
enzymes. Sindhu et al. (2017) reported the production of xylanase from ultrasound-
assisted alkali-pretreated CPHR (USAAP CPHR). Solid-state fermentation was car-
ried out with USAAP CPHR by Streptomyces sp. and Bacillus pumilus. The strains
produced 118 and 151 IU/gds of xylanase, respectively. This is the first report on
utilization of CPHR for the production of xylanases.
Cellulase is an industrial enzyme, which finds application in the production of
biofuel and other chemicals. Agroresidues for the production of cellulase by
Sporotrichum thermophile LAR5 was evaluated by Bajaj et al. (2014). The study
revealed that agroresidues serve as low-cost substrates for the production of cellu-
lase. Maximum cellulase production (2000 IU/L) was observed with wheat bran fol-
lowed by maize bran and rice husk. Supplementation of peptone showed a
substantial increase in enzyme yield. The enzyme showed activity over a wide
range of pH and temperature. Supplementation of peptone improved the cellulase
production to 7000 IU/L. The cellulase was found suitable for the saccharification
of rice straw depicting its potential in biofuel applications.
Azeri et al. (2010) developed a strategy for cellulase-free xylanase production by
Bacillus strain and its application in biobleaching of kraft pulp. Wheat straw, corn-
cob was found to be a suitable substrate for the production of xylanase. The enzyme

was stable up to 60 C and pH 9.0 indicating its potential as a biobleaching agent.
Effectiveness was evaluated on kraft pulp, and the results indicate that the enzyme
reduced the kappa number and enhanced the brightness indicating its potential in
paper and pulp industry.

11.2.4 Organic acids
Agroresidues serve as a suitable feedstock for the production of different organic
acids such as lactic, fumaric, itaconic, xylonic, and succinic.

11.2.4.1 Lactic acid
Lactic acid finds applications in food, beverages, and personal care products. Lactic
acid can be commercially produced by either chemical synthesis or by fermentation.
It can undergo self-esterification to form polylactic acid that is widely used as an
eco-friendly biopolymer.
Commonly used lignocellulosic biomass for the production of lactic acid
includes corncobs, bagasse, and wood-processing waste.
Empty fruit bunch (EFB), a by-product of palm oil industry serves as a potential
feedstock for the production of lactic acid (Aini et al., 2018). The pretreatment of EFB
was carried out using a barium hydroxide catalyst. The results indicate that the highest