the annual production of about 7,000,000 t, and lactic acid is produced with
150,000 t [13], depicted in Fig. 3.
3 Lactic Acid
Lactic acid or 2-hydroxypropionic acid is composed of both hydroxyl and carboxylic
functional groups that are extensively used in the numerous applications of textile,
food, leather, pharmaceutical, and chemical industries [21]. It could also be utilized
as the feedstocks for polylactic acid production that have been used in the medical
applications, and biodegradable plastics are synthesized from the petroleum
resources. The optical isomers of lactic acid exit as D (À) – and L (+)-lactic acids
[22], and L (+)-lactic acids are mostly considered since they could be assimilated in
the human body.
3.1 Production of Lactic Acid
Though lactic acid could be synthesized either by fermentation or chemical synthesis, microbial fermentative synthesis is mostly preferred since a pure form could be
obtained in this method and a racemic mixture was produced by chemical synthesis.
Due to less energy utilization, suitable lower productive temperature, environmental
sustainability, and greater purity yield made microbial fermentative method to be
dominantly used by the industries [23]. The raw material cost for lactic acid
production plays a vital role, and the study has revealed that the fermentative
production cost is 34% greater than the overall production cost. So various attempts
were made to use agricultural residues, rice bran, green microalga, and paper sludge
as the raw materials for lactic acid production [24].
Production in tonnes
15000
100000
150000
1600000
7000000
Acetic acid Citric acid Lactic acid Gluconic acid Itaconic acid
Fig. 3 Production of
various organic acids
Recent Advances in Organic Acid Production from Microbial Sources by Utilizing. . .
71
150,000 t [13], depicted in Fig. 3.
3 Lactic Acid
Lactic acid or 2-hydroxypropionic acid is composed of both hydroxyl and carboxylic
functional groups that are extensively used in the numerous applications of textile,
food, leather, pharmaceutical, and chemical industries [21]. It could also be utilized
as the feedstocks for polylactic acid production that have been used in the medical
applications, and biodegradable plastics are synthesized from the petroleum
resources. The optical isomers of lactic acid exit as D (À) – and L (+)-lactic acids
[22], and L (+)-lactic acids are mostly considered since they could be assimilated in
the human body.
3.1 Production of Lactic Acid
Though lactic acid could be synthesized either by fermentation or chemical synthesis, microbial fermentative synthesis is mostly preferred since a pure form could be
obtained in this method and a racemic mixture was produced by chemical synthesis.
Due to less energy utilization, suitable lower productive temperature, environmental
sustainability, and greater purity yield made microbial fermentative method to be
dominantly used by the industries [23]. The raw material cost for lactic acid
production plays a vital role, and the study has revealed that the fermentative
production cost is 34% greater than the overall production cost. So various attempts
were made to use agricultural residues, rice bran, green microalga, and paper sludge
as the raw materials for lactic acid production [24].
Production in tonnes
15000
100000
150000
1600000
7000000
Acetic acid Citric acid Lactic acid Gluconic acid Itaconic acid
Fig. 3 Production of
various organic acids
Recent Advances in Organic Acid Production from Microbial Sources by Utilizing. . .
71