TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Polypeptide: (II) has a sequence of (S1). (IV) is a polypeptide having the amino acid sequence of B.breve mbc2g.pk018.j20 gene product, sequence of B.breve gene mbc2g.pk018.j20 signal peptide linked to the amino acid sequence of B.breve mbc2g.pk018.h12 gene, sequence of B.breve gene mbc2g.pk018.j20 signal peptide linked to the amino acid sequence of B.breve mbc2g.pk018.k1 gene, sequence of B.breve gene mbc2g.pk018.j20 signal peptide linked to the amino acid sequence of S.mutans dexB gene, sequence of Bacillus subtilis neural protease gene signal peptide linked to the amino acid sequence of B.breve mbc2g.pk018.h12 gene, sequence of Bacillus subtilis neural protease gene signal peptide linked to the amino acid sequence of B.breve mbc2g.pk018.j20 gene, sequence of Bacillus subtilis neural protease gene signal peptide linked to the amino acid sequence of B.breve mbc2g.pk018.k1 gene, or sequence of Bacillus subtilis neural protease gene signal peptide linked to the amino acid sequence of S.mutans dexB gene. Preferred Nucleic Acid: (I) has a sequence (S2) of Bifidobacterium breve mbc1g.pk007.h12 gene, mbc2g.pk018.j20 gene, or mbc1g.pk026.k1 gene. The alpha(1,6)-linked glucose oligosaccharide hydrolyzing polypeptide encoded by (III), comprises (S1), or comprises an amino acid sequence (S3) of Streptococcus mutans dexB gene, or an amino acid sequence (S4) of Bifidobacterium breve gene mbc2g.pk018.j20 without its native signal peptide sequence. The signal peptide in the chimeric protein is native signal peptide sequence (S5) from B.breve coded by mbc2g.pk018.j20 gene, or the non-native signal peptide sequence (S6) used to target enzymes coded for by B.breve mbc1g.pk026.k1 and S.mutans dexB gene. Preferably, the signal peptide is (S5) or (S6) and the alpha(1,6)-linked glucose oligosaccharide hydrolyzing polypeptide is (S1) (S3) or (S4). The nucleic acid encoding alpha(1,6)-linked glucose oligosaccharide hydrolyzing polypeptide in (II) is a nucleic acid molecule having a sequence of (S2), a sequence of dexB gene, sequence of B.breve gene mbc2g.pk018.j20 without its native signal peptide sequence, sequence of B.breve gene mbc2g.pk018.j20 signal peptide linked to the coding sequence of B.breve mbc2g.pk018.h12 gene, sequence of B.breve gene mbc2g.pk018.j20 signal peptide linked to the coding sequence of B.breve mbc2g.pk018.k1 gene, sequence of B.breve gene mbc2g.pk018.j20 signal peptide linked to the coding sequence of S.mutans dexB gene, sequence of Bacillus subtilis neural protease gene signal peptide linked to the coding sequence of B.breve mbc2g.pk018.h12 gene, sequence of Bacillus subtilis neural protease gene signal peptide linked to the coding sequence of B.breve mbc2g.pk018.j20 gene, sequence of Bacillus subtilis neural protease gene signal peptide linked to the coding sequence of B.breve mbc2g.pk018.k1 gene, or sequence of Bacillus subtilis neural protease gene signal peptide linked to the coding sequence of S.mutans dexB gene. Preferred Chimeric Gene: The regulatory sequence is chosen from CYC1, HIS3, GAL1, GAL10, ADH1, PGK, PHO5, GAPDH, ADC1, TRP1, URA3, LEU2, ENO, TPI, AOX1, lac, ara, tet, trp, IPL, IPR, T7, tac, trc, apr, npr, nos, and GI. Preferred Host Cell: In (VII), (V) is integrated into the chromosome or is plasmid-borne. The host cell is chosen from Aspergillus, Trichoderma, Saccharomyces, Pichia, Candida, Hansenula, Rhodococcus, Acinetobacter, Arthrobacter, Brevibacterium, Acidovorax, Bacillus, Streptomyces, Escherichia, Salmonella, Pseudomonas, or Cornyebacterium. Preferably, the host cell is Escherichia coli. EXAMPLE - Bifidobacterium breve (ATCC 15700) was obtained and suspended in a solution containing 10 mM Na-EDTA and 50 mM Tris-HCl, pH 7.5. Genomic DNA was isolated from B.breve according to standard protocols. Genomic DNA and library construction were prepared according to published protocols (Fraser et. al., Science 270 (5235):397-403 (1995)). Genes encoding isoamylase activity were identified by conducting BLAST searches for similarity to sequences contained in the BLAST nr database. The sequences obtained were analyzed for similarity to all publicly available DNA sequences contained in the nr database using the BLASTN algorithm. The DNA sequences were translated in all reading frames and compared for similarity to all publicly available protein sequences in the nr database using the BLASTP algorithm. All comparisons were done using either the BLASTN or BLASTP algorithm. The studies identified 4 nucleic acid molecules such as mbc1g.pk007.h12, mbc2g.pk018.j20, mbc1g.pk026.k1 from Bifidobacterium breve and dexB from Streptococcus mutans.