A method of producing two or more gene products, the method comprising: growing a culture of a host cell, wherein the host cell comprises two or more types of expression constructs, each designed for the expression of one or more gene products, wherein at least one said gene product is a polypeptide lacking a signal peptide; and wherein the expression construct of each type comprises an inducible promoter and a polynucleotide sequence encoding a gene product and each type of expression construct comprises an inducible promoter that is not an inducible promoter of the expression construct of each other type; and wherein the expression constructs comprised by the host cell each comprise at least one inducible promoter selected from the group consisting of: the araBAD promoter, the prpBCDE promoter, the rhaSR promoter, and the xlyA promoter; and wherein the host cell has a reduced level of gene function of at least one gene, encoding a protein that metabolizes an inducer of at least one said inducible promoter comprised by at least one said expression construct, wherein the at least one gene is selected from the group consisting of araA, araB, araD, prpB, prpD, rhaA, rhaB, rhaD, xylA, and xylB; and adding an inducer of at least one said inducible promoter to the culture. growing a culture of a host cell, wherein the host cell comprises two or more types of expression constructs, each designed for the expression of one or more gene products, wherein at least one said gene product is a polypeptide lacking a signal peptide; and wherein the expression construct of each type comprises an inducible promoter and a polynucleotide sequence encoding a gene product and each type of expression construct comprises an inducible promoter that is not an inducible promoter of the expression construct of each other type; and wherein the expression constructs comprised by the host cell each comprise at least one inducible promoter selected from the group consisting of: the araBAD promoter, the prpBCDE promoter, the rhaSR promoter, and the xlyA promoter; and wherein the host cell has a reduced level of gene function of at least one gene, encoding a protein that metabolizes an inducer of at least one said inducible promoter comprised by at least one said expression construct, wherein the at least one gene is selected from the group consisting of araA, araB, araD, prpB, prpD, rhaA, rhaB, rhaD, xylA, and xylB; and wherein the host cell comprises two or more types of expression constructs, each designed for the expression of one or more gene products, wherein at least one said gene product is a polypeptide lacking a signal peptide; and wherein the expression construct of each type comprises an inducible promoter and a polynucleotide sequence encoding a gene product and each type of expression construct comprises an inducible promoter that is not an inducible promoter of the expression construct of each other type; and wherein the expression constructs comprised by the host cell each comprise at least one inducible promoter selected from the group consisting of: the araBAD promoter, the prpBCDE promoter, the rhaSR promoter, and the xlyA promoter; and wherein the host cell has a reduced level of gene function of at least one gene, encoding a protein that metabolizes an inducer of at least one said inducible promoter comprised by at least one said expression construct, wherein the at least one gene is selected from the group consisting of araA, araB, araD, prpB, prpD, rhaA, rhaB, rhaD, xylA, and xylB; and adding an inducer of at least one said inducible promoter to the culture.