Abstract: A process for deinking wastepaper printed with heat fused inks to provide a source of deinked paper which can be reused or repulped and converted into a recycled paper product comprises immersing the wastepaper in a non-aqueous solvent bath containing a solvent capable of dissolving the binder component of the ink, and subjecting the wastepaper to low frequency ultrasound energy to separate the ink particles from the wastepaper. The separated ink particles may be collected magnetically or otherwise and the excess solvent recovered and reintroduced into the solvent bath.

Abstract: A paper additive of high whiteness and low biological toxicity comprising a whitening amount of a compound of the formula ##STR1## wherein R is H or (C.sub.1 -C.sub.6)alkyl R' is independently H or (C.sub.1 -C.sub.6)alkyl, R" is H or NR'.sub.n, and n is 2 or 3, wherein if n=3 the compound further comprises X.sup.-, wherein X.sup.- is an anion.A paper of high whiteness and low biological toxicity is coated or filled with the above additive, and a food product is packaged with the paper of this invention.

Abstract: Solutions containing peroxidase enzymes may be treated to increase their stability and shelf life by reducing their protease level and filtering through a microporous filter to remove any microbial contamination that might secrete additional protease enzymes.