the feasibility of grape pomace for the production of xylanases by A. awamori. Maximum invertase production under
optimized conditions using fruit peel as a substrate has been
reported. In the same way, A. niger was combined with a
number of carbon sources, like fruit peel, lactose, fructose,
and invertase. Among them, fructose has been considered as
an important carbon source for the extraction of extracellular
invertase. Various agro-industrial residues have been
extensively studied for the production of proteases along
with FVW (Bharathiraja et al. 2017). In the other study of
alkaline protease using chickpea waste and various
agro-industrial waste produced by Bacillus sp. (Sagar et al.
2018; Prakasham et al. 2006).
2.2 Industrial Products
The fruit and agricultural sectors are growing at a rapid rate;
the resulting waste generation embodies major environmental challenges. Fruits and vegetables constitute the
highest rate of waste but are high in nutrients. The
underutilized waste may produce disease-causing microbes
if the residue is left unprocessed. These wastes can be used
as raw materials for the production of valuable products or as
a source of renewable energy. Consistency in the availability
of cheaper raw materials is essential to reduce the cost of
production and to manage the efficient operation. During the
twentieth century, the thriving use of agricultural waste as
carbon and nitrogen sources for antibiotic fermentation
emerged. Linking waste streams from several sectors to
agro-based enterprises for efficient recovery would help to
solve the problem of waste accumulation. This calls for
realistic studies on the recovery of FVW for the manufacture
of value-added goods.
2.2.1 Organic Acids
A number of organic acids can be extracted from FVW. Dry
apricot waste is used as a base for the processing of citric
acid using A. niger by fermentation. It was observed that
SSF of A.foetidus using dried apricot waste as a substrate
produced a high quantity of citric acid compared to other
FVW like apple pomace, wheat, or rice bran. Most citric
acids are produced mainly by SSF of starch or molasses
exclusively by A.niger. As substrates for citric acid production, several types of FVW, molasses, and cassava
bagasse have been examined. The apple waste is found to be
an effective substrate for the production of citric acid. It was
also produced from the date extract/molasses using A.niger
ATCC 6275 and 9642 and from the date waste using A.niger
ANSS-B5. Lactic acid has a crucial role in the carboxylic
acid family due to its use in both the food and non-food
commodities. This is used as a preservative and as an
acidulant in the food industry. However, the commercial
production of lactic acid is costly because of the high cost of
the raw materials used. It can be saved through the use of
biological waste. Pineapple waste can also be used for lactic
acid production by using SSF. Sanada et al. have developed
a bioprocess for the production of lactic acid that has various
applications in the cosmetic, food, chemical, and pharmaceutical industries. The potential of mango peel as a substrate for the low-cost production of lactic acid has also been
investigated. In this study, mango peel was fermented
directly using bacteria with amylolytic and lactic acid production capabilities. Maximum production of 17.48 g/l of
lactic acid was achieved by optimizing fermentation conditions. The mesophilic microbial system that can work at 35 °
C has been used in this study and appears to have a practical
advantage due to its low cost. In another study, a lactic acid
concentration of 63.33 g/l of fermentation media was
obtained from the fermentation of mango peel by Lactobacillus casei. In order to minimize the cost of lactic acid
production, low-priced raw materials, e.g., FVW such as
banana, sapota, papaya, corn cob, and potato have been
reported. All the substrates tested assisted the growth and
development of lactic acid. An efficient concentration of
lactic acid (72 g/l) was achieved with the fermentation of
sapota peel. Nancib et al. used the date juice as a substrate
for the production of lactic acid using L. caseisubsprhamnosus or Lactobacillus delbrucki. Ferulic acid is the most
common hydroxyl cinnamic acid present in the walls of the
plant cells. This phenolic antioxidant is widely used in the
food and cosmetics industries. Pineapple, orange, and
pomegranate peels have been used for ferulic acid extraction.
Gallic acid, catechin, epicatechin, and ferulic acid were
found to be the major polyphenols in pineapple peels.
Ferulic acid is beneficial for the viability and motility of
sperm in both fertile and infertile individuals, and the
reduction of lipid by oxidative damage to sperm membranes
and increased intracellular cAMP and cGMP may be associated with these benefits. It is possible that ferulic acid may
be used to cure asthenozoospermic infertility. Acetic acid,
another organic acid, can be produced from carrots and
white radish leaves. Carrot leafage was used as a substrate
for the two-stage hydrothermal production of acetic acid
resulting in a high yield. Organic acid production by the use
of vegetable waste thus serves two purposes: to reduce the
cost of raw materials and to recycle waste, thus reducing the
pollution problem (Wadhwa et al. 2015).
Sugarcane bagasse powder was found to be suitable for
the fermentation of itaconic acid. Among the various fungi
184
R. Reshmy et al.
optimized conditions using fruit peel as a substrate has been
reported. In the same way, A. niger was combined with a
number of carbon sources, like fruit peel, lactose, fructose,
and invertase. Among them, fructose has been considered as
an important carbon source for the extraction of extracellular
invertase. Various agro-industrial residues have been
extensively studied for the production of proteases along
with FVW (Bharathiraja et al. 2017). In the other study of
alkaline protease using chickpea waste and various
agro-industrial waste produced by Bacillus sp. (Sagar et al.
2018; Prakasham et al. 2006).
2.2 Industrial Products
The fruit and agricultural sectors are growing at a rapid rate;
the resulting waste generation embodies major environmental challenges. Fruits and vegetables constitute the
highest rate of waste but are high in nutrients. The
underutilized waste may produce disease-causing microbes
if the residue is left unprocessed. These wastes can be used
as raw materials for the production of valuable products or as
a source of renewable energy. Consistency in the availability
of cheaper raw materials is essential to reduce the cost of
production and to manage the efficient operation. During the
twentieth century, the thriving use of agricultural waste as
carbon and nitrogen sources for antibiotic fermentation
emerged. Linking waste streams from several sectors to
agro-based enterprises for efficient recovery would help to
solve the problem of waste accumulation. This calls for
realistic studies on the recovery of FVW for the manufacture
of value-added goods.
2.2.1 Organic Acids
A number of organic acids can be extracted from FVW. Dry
apricot waste is used as a base for the processing of citric
acid using A. niger by fermentation. It was observed that
SSF of A.foetidus using dried apricot waste as a substrate
produced a high quantity of citric acid compared to other
FVW like apple pomace, wheat, or rice bran. Most citric
acids are produced mainly by SSF of starch or molasses
exclusively by A.niger. As substrates for citric acid production, several types of FVW, molasses, and cassava
bagasse have been examined. The apple waste is found to be
an effective substrate for the production of citric acid. It was
also produced from the date extract/molasses using A.niger
ATCC 6275 and 9642 and from the date waste using A.niger
ANSS-B5. Lactic acid has a crucial role in the carboxylic
acid family due to its use in both the food and non-food
commodities. This is used as a preservative and as an
acidulant in the food industry. However, the commercial
production of lactic acid is costly because of the high cost of
the raw materials used. It can be saved through the use of
biological waste. Pineapple waste can also be used for lactic
acid production by using SSF. Sanada et al. have developed
a bioprocess for the production of lactic acid that has various
applications in the cosmetic, food, chemical, and pharmaceutical industries. The potential of mango peel as a substrate for the low-cost production of lactic acid has also been
investigated. In this study, mango peel was fermented
directly using bacteria with amylolytic and lactic acid production capabilities. Maximum production of 17.48 g/l of
lactic acid was achieved by optimizing fermentation conditions. The mesophilic microbial system that can work at 35 °
C has been used in this study and appears to have a practical
advantage due to its low cost. In another study, a lactic acid
concentration of 63.33 g/l of fermentation media was
obtained from the fermentation of mango peel by Lactobacillus casei. In order to minimize the cost of lactic acid
production, low-priced raw materials, e.g., FVW such as
banana, sapota, papaya, corn cob, and potato have been
reported. All the substrates tested assisted the growth and
development of lactic acid. An efficient concentration of
lactic acid (72 g/l) was achieved with the fermentation of
sapota peel. Nancib et al. used the date juice as a substrate
for the production of lactic acid using L. caseisubsprhamnosus or Lactobacillus delbrucki. Ferulic acid is the most
common hydroxyl cinnamic acid present in the walls of the
plant cells. This phenolic antioxidant is widely used in the
food and cosmetics industries. Pineapple, orange, and
pomegranate peels have been used for ferulic acid extraction.
Gallic acid, catechin, epicatechin, and ferulic acid were
found to be the major polyphenols in pineapple peels.
Ferulic acid is beneficial for the viability and motility of
sperm in both fertile and infertile individuals, and the
reduction of lipid by oxidative damage to sperm membranes
and increased intracellular cAMP and cGMP may be associated with these benefits. It is possible that ferulic acid may
be used to cure asthenozoospermic infertility. Acetic acid,
another organic acid, can be produced from carrots and
white radish leaves. Carrot leafage was used as a substrate
for the two-stage hydrothermal production of acetic acid
resulting in a high yield. Organic acid production by the use
of vegetable waste thus serves two purposes: to reduce the
cost of raw materials and to recycle waste, thus reducing the
pollution problem (Wadhwa et al. 2015).
Sugarcane bagasse powder was found to be suitable for
the fermentation of itaconic acid. Among the various fungi
184
R. Reshmy et al.