{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T00:24:01Z","timestamp":1793060641083,"version":"4.5.0"},"reference-count":38,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T00:00:00Z","timestamp":1765411200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Bioeng. Biotechnol."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Lactose intolerance affects 85%\u201395% of Chinese adults, creating substantial demand for low-lactose dairy products. This study aimed to develop a cost-effective \u03b2-galactosidase production process through solid-state fermentation (SSF) using agricultural byproducts.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A high-yielding strain was isolated from Tibetan fermented yak milk and identified through morphological, biochemical, and 16S rDNA sequence analysis. Solid-state fermentation conditions were optimized using single-factor experiments and Box-Behnken response surface methodology. Enzymatic properties were characterized, and the enzyme was applied to milk lactose hydrolysis. Techno-economic and environmental impact analyses were conducted.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Lactobacillus plantarum LP-15 exhibited initial enzyme activity of 44.7 U\/g. Optimal SSF conditions were determined as substrate ratio of wheat bran:soybean meal:whey powder (6:3:1), 37 \u00b0C, pH 6.5, and 55% moisture content, achieving enzyme activity of 186.3 U\/g (4.17-fold improvement). The enzyme exhibited optimal activity at pH 6.5 and 42 \u00b0C, with Km of 2.8 mM and catalytic efficiency of 5.3 \u00d7 10\n                      <jats:sup>4<\/jats:sup>\n                      M\n                      <jats:sup>\u22121<\/jats:sup>\n                      s\n                      <jats:sup>\u22121<\/jats:sup>\n                      . Milk lactose was reduced by 81.9% within 4 h using 2.0 U\/mL enzyme at 40 \u00b0C, meeting the low-lactose standard (\u22640.1%). SSF reduced production costs by 35.7%, water usage by 94%, and CO\n                      <jats:sub>2<\/jats:sub>\n                      emissions by 62.4% compared to liquid fermentation.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>This study provides an economically viable and environmentally sustainable solution for low-lactose dairy production in China, establishing independent intellectual property rights while addressing nutritional needs of lactose-intolerant populations through circular utilization of agricultural by products.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fbioe.2025.1708601","type":"journal-article","created":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T09:41:37Z","timestamp":1765446097000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":9,"title":["Optimization of solid-state fermentation conditions for high \u03b2-galactosidase-producing lactic acid bacteria and its application in low-lactose dairy products"],"prefix":"10.3389","volume":"13","author":[{"given":"Zhanjia","family":"Zhang","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2025,12,11]]},"reference":[{"key":"B2","volume-title":"Green chemistry: theory and practice","author":"Anastas","year":"1998"},{"key":"B3","doi-asserted-by":"publisher","first-page":"1463785","DOI":"10.3389\/fceng.2024.1463785","article-title":"The role of solid-state fermentation to transform existing waste treatment plants based on composting and anaerobic digestion into modern organic waste-based biorefineries, in the framework of circular bioeconomy","volume":"6","author":"Artola","year":"2024","journal-title":"Front. 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