Saving energy upon water removal in drying by making the α-polymorph of L-glutamic acid

Tu Lee, Chia Ling Yang, Hung Lin Lee

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Drying is an energy-intensive operation for the separation of a desired solid product, when it consumes 12–20% of the entire energy used in manufacturing processes. Without changing the existing drying method or equipment, making α-form of L-glutamic acid (α-Glu) by reactive crystallization can reduce the energy consumption for drying in terms of much less initial moisture content of 23.32% and time of 4.67 h, as compared to 48.52% and 6 h for its β-form in the present study. Upon drying, α-Glu shows less affinity for hydrogen bonding with water, as ammonia cations on α-carbon of L-Glu are projected on the α-Glu’s surface. On the contrary, more hydrophilic carboxylate anions on α-carbon are exposed on the surface of β-Glu, which tends to form agglomerates during reactive crystallization, causing stronger interaction with water. As a consequence, 35% of energy utilization in drying can be saved by making α-Glu.

Original languageEnglish
Pages (from-to)1948-1965
Number of pages18
JournalSeparation Science and Technology
Issue number12
StatePublished - 2022


  • Energy efficiency
  • amino acids
  • fermentation
  • particle size
  • powder handling


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