NOVELTY - A recombinant expression vector comprising isolated polynucleotide encoding yeast small nucleolar RNA (SNR)84, is new.    USE - The vector is useful for transformation of yeast used for producing biofuel chosen from ethanol, propanol, butanol and acetone, from galactose ( greater than or equal to 4%)-containing carbon source consisting of galactose or mixture of glucose and galactose, preferably hydrolyzate of algae biomass (all claimed).    ADVANTAGE - The volumetric productivity of biofuel e.g. ethanol is increased by 48% in SNR84-overexpressing strain compared to control strain, as galactose is rapidly catabolized by the SNR84-overexpressing strain.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) recombinant microorganism transformed with the above-mentioned recombinant vector;    (2) producing biofuel from a galactose-containing carbon source, involves (a) incubating the above-mentioned recombinant microorganism in a galactose-containing carbons source such that the recombinant microorganism produces a biofuel, or (b) transforming a yeast with the above-mentioned, culturing the recombinant yeast strain in galactose-containing carbon source, and overexpressing yeast SNR84 in the recombinant yeast strain; and    (3) screening yeast for a gene which increases galactose catabolism when the gene is overexpressed, involves constructing a yeast genomic DNA library using a multi-copy plasmid comprising a tryptophan promoter, transforming a yeast with the constructed genomic DNA library such that a library of the transformed yeast in which yeast genes inserted in the multi-copy plasmid are overexpressed, culturing the transformed yeast in a medium containing galactose as a carbon source, screening the transformed yeast for colonies having increased galactose catabolism, where the screening comprises identifying fast-growing colonies of yeast through serial subculture, isolating the plasmid from the screened transformed yeast, and identifying a yeast genomic sequence inserted in the isolated plasmid.