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manipulation of certain pathway also increases the yield of bio-based chemicals.
The concentration of the final bio-based product is quite low due to product inhibi-
tion and limited outlet. The use of chemical or directed mutagenesis was reported
to increase the yield at better chances (Wittlich et al., 2000; Reimann et al., 1998;
Palsson et al., 1981). Bio-based chemical production is challenged by abundance of
target as integrated biorefinery process is still in the state of infancy. Identification
and rational selection of new structures are also a challenging task in this industry.

6.4 Production of platform chemicals—an outlook

Biological production of chemicals is one of the sustained biorefining technologies.
This technology was widely used due to its high value and low material demand.
During the 20th century, many commodity chemicals such as acetic, citric, lactic
acid, and n-butanol were produced by fermentation techniques (Dodds and Gross,
2007). Organic acids produced by microbial fermentation constitute a key group
among top platform chemicals. Advancement in metabolic engineering for the
development of microbial cell factories helps in the production of industrially
important compounds. Production and commercialization of organic acids, succinic
acid, and 3-hydroxypropionic acid with a particular emphasis are gaining impor-
tance due to concerning product yield, productivity, and concentrations (Chen and
Nielson, 2016). The bio-based chemicals were also used in automotive industries,
and the growth has reached better heights (McLaughlin, 2008; Khalil, 2008). A
classical chemical method with integrated biorefinery approach is used for the pro-
duction of bio-based chemicals such that the carbon carbon double bonds are con-
verted to alcohols and methoxy groups. The biotechnological routes were used for
the production of levulinic acid (Farone and Cuzens, 2000; Lucia et al., 2006). The
short chains C5 with reactive functional groups are converted into wide range of
products such as resins, plasticizers, xylene, benzene, and toluene (Van Haveren
et al., 2007). The possible methods for the production of value-added chemicals
include

1. catalysis,
2. condensation polymerization,
3. fermentation, and
4. ionic liquid-phase reaction.
Catalysis has been employed for the production of fuels to high-value chemicals
by the conversion of efficient biomass. Fischer Tropsch synthesis along with plati-
num catalysis was employed for the production of chemicals. Biocatalysis was
reported for the production of fine chemicals and pharma products. This biocataly-
sis was used, because they selectively catalyze reactions for the formation of
desired products. The production of specialty chemicals was mainly carried out
using biocatalysis as they help in the catalysis of products that are not possible to
catalyze via chemical reactions (Pagliaro and Rossi, 2008; Thomas et al., 2002).