TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: In the process for producing a biobased GBL product, the genetically engineered biomass is from a recombinant host having a poly-4-hydroxybutyrate pathway, where the host has an inhibiting mutation in its coenzyme A (CoA)-independent NAD-dependent succinic semialdehyde dehydrogenase gene or its CoA-independent NADP-dependent succinic semialdehyde dehydrogenase gene, or having the inhibiting mutations in both genes, and having stably incorporated one or more genes encoding one or more enzymes selected from a succinyl-CoA:coenzyme A transferase where the succinyl-CoA:coenzyme A transferase is able to convert succinate to succinyl-CoA, a succinate semialdehyde dehydrogenase where the succinate semialdehyde dehydrogenase is able to convert succinyl-CoA to succinic semialdehyde, a succinic semialdehyde reductase where the succinic semialdehyde reductase is able to convert succinic semialdehyde to 4-hydroxybutyrate, a CoA transferase where the CoA transferase is able to convert 4-hydroxybutyrate to 4-hydroxybutyryl-CoA, and a polyhydroxyalkanoate synthase where the polyhydroxyalkanoate synthase is able to polymerize 4-hydroxybutyryl-CoA to poly-4-hydroxybutyrate. The genetically engineered biomass is from a recombinant host having stably incorporated one or more genes encoding one or more enzymes selected from: a phosphoenolpyruvate carboxylase where the phosphoenolpyruvate carboxylase is able to convert phosphoenolpyruvate to oxaloacetate, an isocitrate lyase where the isocitrate lyase is able to convert isocitrate to glyoxalate, a malate synthase where the malate synthase is able to convert glyoxalate to malate and succinate, a succinate-CoA ligase (ADP-forming) where the succinate-CoA ligase (ADP-forming) is able to convert succinate to succinyl-CoA, an NADP-dependent glyceraldeyde-3-phosphate dehydrogenase where the NA P-dependent glyceraldeyde-3-phosphate dehydrogenase is able to convert glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate forming NADPH+H+, an NAD-dependent glyceraldeyde-3 -phosphate dehydrogenase where the NAD-dependent glyceraldeyde-3-phosphate dehydrogenase is able to convert glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate forming NADH+H+ a butyrate kinase where the butyrate kinase is able to convert 4-hydroxybutyrate to 4-hydroxybutyryl-phosphate, a phosphotransbutyrylase where the phosphotransbutyrylase is able to convert 4-hydroxybutyryl-phosphate to 4-hydroxybutyryl-CoA; and optionally having a disruption in one or more genes selected from yneI, gabD, pykF, pykA, maeA and maeB. The process further includes an initial step of culturing a recombinant host with a renewable feedstock to produce a poly-4-hydroxybutyrate biomass. A source of the renewable feedstock is selected from glucose, fructose, sucrose, arabinose, maltose, lactose, xylose, fatty acids, vegetable oils, and biomass derived synthesis gas or their combination. The biomass host is bacteria, yeast, fungi, algae, cyanobacteria, or their mixture. The biomass host is bacteria, where the bacteria is selected from Escherichia coli, Alcaligenes eutrophus (renamed as Ralstonia eutropha), Bacillus spp., Alcaligenes latus, Azotobacter, Aeromonas, Comamonas, Pseudomonas, Ralstonia, Klebsiella, Synechococcus sp. PCC7002, Synechococcus sp. PCC7942, Synechocystis sp. PCC6803, Thermosynechococcus elongatus BP-I, Chlorobium tepidum, Chloroflexus aurianticus, Chromatium tepidum, Chromatium vinosum, Rhodospirillum rubrum, Rhodobacter capsulatus, and Rhodopseudomonas palustris. The recombinant host is algae. Heating is at 100-350 degrees C. The catalyst is sodium carbonate or calcium hydroxide, where the weight percent of catalyst is 4-50%. Heating reduces the water content of the biomass to 5 wt%, or less. Heating temperature is 200-350 degrees C. Heating is for 30 seconds to 5 minutes or 5 minutes to 2 hours. The process further comprises recovering the GBL product. The GBL product comprises less than 5% by weight of side products. The GBL is further processed to form one or more of the following: 1,4-butanediol (BDO), tetrahydrofuran (THF), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), 2-pyrrolidinone, N-vinylpyrrolidone (NVP) and polyvinylpyrrolidone (PVP). The weight % of the catalyst is 4- 50%, and the heating is at 300 degrees C. The catalyst is 4% by weight calcium hydroxide and the heating is at 300 degrees C. Product is 85% by weight or greater based on one gram of a GBL in the product per gram of poly-4-hydroxybutyrate. Preferred Biobased GBL Product: The GBL product comprises less than 5% by weight of side products. The GBL in the product has 100% biobased carbon content. EXAMPLE - No suitable example given.