procyanidin group and catechins, epicatechins, and their
esterified derivatives. The profile of phenolic acids revealed
many activities including, antimicrobial, antioxidant, anticarcinogenic, antimutagenic, and some other biological
properties (Xu 2008). Substituted derivatives of hydroxybenzoic and hydroxycinnamic acids are the predominant
phenolic acids. The most common hydroxycinnamic acids
are caffeic, p-coumaric, and ferulic acids, which frequently
occur in food as simple esters with quinic acid or glucose
(Shahidi and Ambigaipalan 2015) while the most common
benzoic acid is gallic acid, occurring in red fruits, onions,
and black radish (Xu et al. 2017).
Plants are the core bases of natural antimicrobials, i.e.,
compounds accomplished to inhibit the microorganism’s
growth. These compounds are used along with older
antibiotics to intensify the potency to evade the development
of microbial resistance. The plant compounds that are
broadly employed for antimicrobial purposes contain terpenoids, alkaloids, phenolics, and sulfur-containing compound (Khameneh et al. 2019). Therefore, more than 30,000
antimicrobial ingredients are extracted from different plants
with effective antimicrobial potential (Tajkarimi et al. 2010).
Plants are a large stake as bases of natural antimicrobials
agents, and in this sense, the use of plant parts is usually
thrown as wastes, and this agro-waste is a useful, sustainable
and safe selection in the search of new antimicrobial
compounds.
3.2 Bioactive Compounds Recovery
from Agro-Industrial Wastes Useful
Fermentation and Food Industry
The agro-industrial products generate a large number of
fruits and vegetable peel, which create problems related to
municipal landfills and safe management of these wastes.
These wastes highly biodegradable and leachate produce
methane, which creates problems for the environment (Misi
and Forster 2002). These agro-industrial wastes mostly
consist of seeds, bark, peels, pulp, etc., it can be used to
extract high-value bioactives including enzymes, essential
oils proteins, and some other compounds with potential
biological activity that can be recovered and used for different useful purposes (Schieber et al. 2001). Figure 3 represents the usage of agro-industrial wastes as a natural
source in fermentation and food industries for bioactive
compounds production.
3.3 Bio-Surfactants Production
Surfactants are chemical substances, known for their
potential to minimize surface tension and ultimately leading
to the proper dissolution of immiscible solvents. Chemical
synthesis is generally a common synthesis strategy for these
surface-active compounds that cause severe side effects and
impact in environmental hazards. The bio-surfactants are
bioactive macromolecules generated by a variety of different
microorganisms having hydrophobic and hydrophilic characteristics. They are the best alternative of chemical-based
surfactants in terms of biodegradability, low toxic profile
environmentally close to nature, and production via low-cost
agro-industrial raw materials as beneficial part of “green
technology” (Mukherjee et al. 2006). Bio-surfactants consist
of long-listed chemical constituents; lipopeptides, phospholipids, glycolipids, lipoproteins, and lipid-polysaccharide
derivatives. They present various applications as emulsifiers,
conditioners, cosmetics, and food industries (Singh et al.
2007) and are also found effective in tackling environmental
pollution through bioremediation (Banat and Thavasi 2019).
Despite having several commercially viable and environmentally friendly properties, the generation of
industrial-scale bio-surfactants is still in its initial stages
because of the utilization of expensive substrates with low
production yield. The selection of a suitable substrate is an
important step, as the substrate accounts for about 50% of
the overall bioprocess cost of bio-surfactant development
(Rodrigues et al. 2006; Asgher et al. 2019). Therefore,
reducing the cost of the fermentation substrate could significantly reduce the overall cost of the bio-surfactant generation. A huge amount of renewable agro-industrial
byproducts is generally disposed of in the environment
including sugarcane bagasse, coconut husk, wheat straw,
rice straw, and vegetables and fruits waste among others
(Bilal et al. 2017; Arevalo-Gallegos et al. 2017). The utilization of such organic byproducts as raw substances for the
development of value-added substances like bio-surfactants
would not only reduce the overall bioprocess cost but also
minimize the risk of environmental pollution. The generation of industrial-scale bio-surfactant requires in-depth
studies to formulate and optimize nutritionally balanced
growth media and certain substrates, which give the best
bio-surfactant yield.
The agriculture processing industry generates a considerable amount of organic waste and byproducts. The processing of corn, barley grains, rice, and wheat release a huge
amount of organic waste rich in carbohydrates. Therefore,
various researches have been conducted to explore the
potentialities of low-cost agro-industrial byproducts including starchy substances, oil wastes, plant oils, and distillery
wastes for cost effect bio-surfactants generation presented in
Table 4. Microbes, due to their metabolic variety, could use
a variety of nutrients for their growth and can produce different kinds of bio-surfactants. However, researchers are
required to study the induction of a desired biochemical
pathway to improve the generation of a specific type of
358
T. Mehmood et al.
esterified derivatives. The profile of phenolic acids revealed
many activities including, antimicrobial, antioxidant, anticarcinogenic, antimutagenic, and some other biological
properties (Xu 2008). Substituted derivatives of hydroxybenzoic and hydroxycinnamic acids are the predominant
phenolic acids. The most common hydroxycinnamic acids
are caffeic, p-coumaric, and ferulic acids, which frequently
occur in food as simple esters with quinic acid or glucose
(Shahidi and Ambigaipalan 2015) while the most common
benzoic acid is gallic acid, occurring in red fruits, onions,
and black radish (Xu et al. 2017).
Plants are the core bases of natural antimicrobials, i.e.,
compounds accomplished to inhibit the microorganism’s
growth. These compounds are used along with older
antibiotics to intensify the potency to evade the development
of microbial resistance. The plant compounds that are
broadly employed for antimicrobial purposes contain terpenoids, alkaloids, phenolics, and sulfur-containing compound (Khameneh et al. 2019). Therefore, more than 30,000
antimicrobial ingredients are extracted from different plants
with effective antimicrobial potential (Tajkarimi et al. 2010).
Plants are a large stake as bases of natural antimicrobials
agents, and in this sense, the use of plant parts is usually
thrown as wastes, and this agro-waste is a useful, sustainable
and safe selection in the search of new antimicrobial
compounds.
3.2 Bioactive Compounds Recovery
from Agro-Industrial Wastes Useful
Fermentation and Food Industry
The agro-industrial products generate a large number of
fruits and vegetable peel, which create problems related to
municipal landfills and safe management of these wastes.
These wastes highly biodegradable and leachate produce
methane, which creates problems for the environment (Misi
and Forster 2002). These agro-industrial wastes mostly
consist of seeds, bark, peels, pulp, etc., it can be used to
extract high-value bioactives including enzymes, essential
oils proteins, and some other compounds with potential
biological activity that can be recovered and used for different useful purposes (Schieber et al. 2001). Figure 3 represents the usage of agro-industrial wastes as a natural
source in fermentation and food industries for bioactive
compounds production.
3.3 Bio-Surfactants Production
Surfactants are chemical substances, known for their
potential to minimize surface tension and ultimately leading
to the proper dissolution of immiscible solvents. Chemical
synthesis is generally a common synthesis strategy for these
surface-active compounds that cause severe side effects and
impact in environmental hazards. The bio-surfactants are
bioactive macromolecules generated by a variety of different
microorganisms having hydrophobic and hydrophilic characteristics. They are the best alternative of chemical-based
surfactants in terms of biodegradability, low toxic profile
environmentally close to nature, and production via low-cost
agro-industrial raw materials as beneficial part of “green
technology” (Mukherjee et al. 2006). Bio-surfactants consist
of long-listed chemical constituents; lipopeptides, phospholipids, glycolipids, lipoproteins, and lipid-polysaccharide
derivatives. They present various applications as emulsifiers,
conditioners, cosmetics, and food industries (Singh et al.
2007) and are also found effective in tackling environmental
pollution through bioremediation (Banat and Thavasi 2019).
Despite having several commercially viable and environmentally friendly properties, the generation of
industrial-scale bio-surfactants is still in its initial stages
because of the utilization of expensive substrates with low
production yield. The selection of a suitable substrate is an
important step, as the substrate accounts for about 50% of
the overall bioprocess cost of bio-surfactant development
(Rodrigues et al. 2006; Asgher et al. 2019). Therefore,
reducing the cost of the fermentation substrate could significantly reduce the overall cost of the bio-surfactant generation. A huge amount of renewable agro-industrial
byproducts is generally disposed of in the environment
including sugarcane bagasse, coconut husk, wheat straw,
rice straw, and vegetables and fruits waste among others
(Bilal et al. 2017; Arevalo-Gallegos et al. 2017). The utilization of such organic byproducts as raw substances for the
development of value-added substances like bio-surfactants
would not only reduce the overall bioprocess cost but also
minimize the risk of environmental pollution. The generation of industrial-scale bio-surfactant requires in-depth
studies to formulate and optimize nutritionally balanced
growth media and certain substrates, which give the best
bio-surfactant yield.
The agriculture processing industry generates a considerable amount of organic waste and byproducts. The processing of corn, barley grains, rice, and wheat release a huge
amount of organic waste rich in carbohydrates. Therefore,
various researches have been conducted to explore the
potentialities of low-cost agro-industrial byproducts including starchy substances, oil wastes, plant oils, and distillery
wastes for cost effect bio-surfactants generation presented in
Table 4. Microbes, due to their metabolic variety, could use
a variety of nutrients for their growth and can produce different kinds of bio-surfactants. However, researchers are
required to study the induction of a desired biochemical
pathway to improve the generation of a specific type of
358
T. Mehmood et al.