Enzyme classification under excise law prevails over culture of micro-organisms where the product is most akin to an enzyme.

Penicillin G. Amidase Biocatalyst manufactured from cultivated E. coli cells was treated as enzyme-like and most akin to an enzyme, so classification under Heading 35.07 prevailed over Heading 30.02 for cultures of micro-organisms. Technical literature, HSN notes, and the Chief Chemist's opinion supported that treatment, while the record did not establish the product as a culture of micro-organisms. On limitation, the extended period under the proviso to Section 11A was unavailable because the classification lists disclosed the product and had departmental approval, with no suppression, misstatement, or intent to evade shown. The first demand was therefore time-barred, while the remaining demands within the normal period remained sustainable.

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Issues: (i) Whether Penicillin G. Amidase Biocatalyst was classifiable under Heading 35.07 as an enzyme or under Heading 30.02 as a culture of micro-organisms; (ii) Whether the extended period under the proviso to Section 11A of the Central Excise Act, 1944 could be invoked.

Issue (i): Whether Penicillin G. Amidase Biocatalyst was classifiable under Heading 35.07 as an enzyme or under Heading 30.02 as a culture of micro-organisms

Analysis: The product was manufactured from cultivated E. Coli whole cells containing Penicillin G. Amidase activity and was used as a repeated catalyst in the manufacture of 6-APA and 7-ADCA. The available technical literature, the HSN notes, the research article on penicillin acylase, and the opinion of the Chief Chemist all supported the view that the product was enzyme-like and more akin to enzymes than to cultures of micro-organisms. The material placed on record did not establish that the product was a culture of micro-organisms within Heading 30.02. Applying the residuary principle of classification by the goods to which they are most akin, the product fell under Heading 35.07.

Conclusion: The classification under Heading 35.07 was upheld and the assessee's claim to Heading 30.02 failed.

Issue (ii): Whether the extended period under the proviso to Section 11A of the Central Excise Act, 1944 could be invoked

Analysis: The classification lists had disclosed the product description and had been approved by the department. The record did not justify a finding of suppression, misstatement, or intentional evasion. On those facts, invocation of the extended period was not warranted for the first demand covered by the longer period, though the later demands raised within the normal limitation period remained sustainable in accordance with the classification finding.

Conclusion: The extended period was not available and the demand covered by it was time-barred, while the remaining demands were sustained.

Final Conclusion: The appeal succeeded only to the extent of the limitation objection, but failed on the classification issue, with the larger part of the duty demand being maintained.

Ratio Decidendi: Where a product is manufactured from cultivated microbial cells and the record shows that it functions as an enzyme or is most akin to an enzyme, classification under the enzyme heading prevails over a culture-of-micro-organisms heading; the extended limitation period cannot be invoked absent suppression or misstatement established from the record.

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