Heidi Schumann / New York Times News Service file photoAlgae grows in petri dishes at Solazyme’s research labs in South San Francisco in 2011. Oil from genetically modified algae like these is just one way in which synthetic biology is being used in the manufacture of consumer goods, an increasingly controversial subject that corporations have long been reluctant to discuss.

Consumer products containing ingredients made using an advanced form of engineering known as synthetic biology are beginning to show up more often on grocery and department store shelves.

A liquid laundry detergent made by Ecover, a Belgian company that makes “green” household products including the Method line, contains an oil produced by algae whose DNA sequence was changed in a lab, according to Tom Domen, the company’s manager for long-term innovation.

Ecover calls the algae-produced oil a “natural” replacement for palm kernel oil, which is in such high demand that environmentalists are concerned that tropical rain forests are being felled to grow palm trees, disturbing ecosystems and threatening endangered animals.

“Finding a sustainable source of palm oil is, of course, difficult,” Domen said. “This new oil is a more sustainable alternative from a new technology.”

That technology, synthetic biology, involves the creation of biological systems intended for specific purposes. Originally aimed at producing biofuels, the technology has been around for about 20 years, but applications have only recently begun to emerge across several industries including cosmetics, flavorings and scents.

Unilever recently announced that it was using algae oil for its popular soap Lux and that the oil was made by the company Solazyme. The two companies signed an agreement in 2009 to explore use of Solazyme’s products in the consumer giant’s goods.

But in an illustration of how reluctant companies may be to disclose the use of synthetic biology, it is unclear whether the oil in Lux was generated through the same synthetic process as Ecover’s detergent. Unilever declined to comment.

These announcements have prompted some environmental groups and consumer activists to call for labeling that would disclose whether synthetic biology was used to make product ingredients.

“We support Ecover’s determination to move away from using unsustainable palm oil, but would ask your company to reconsider the false solution of using ingredients derived from the new genetic engineering — synthetically modified organisms,” the groups wrote in a letter to the company.

An ingredient crucial to malaria drugs, artemisinin, is already being produced from a yeast altered through synthetic biology.

Solazyme pointed to rennet, a key processing aid in cheese-making that requires an enzyme called chymosin to promote clotting. Traditionally, calves’ stomachs provided that enzyme, but since the late 1990s, it has been generated by a microbe whose genetic code was altered with the insertion of a single bovine gene, and that process is widely in use now. Some newer processes using synthetic biology involve techniques that extensively alter genetic code. Those include “artificial gene synthesis,” in which DNA is created on computers and inserted into organisms, and other methods for changing DNA sequences and genes within organisms to alter their function.

Such techniques are used to coax bacteria, fungi and other organisms into producing substances they do not naturally produce. The algae now churning out the oil Ecover is using in its laundry detergent, for instance, would not generate such oil without genetic tinkering.

“It is not possible to harvest algae in the sea and get this oil,” Domen said.

According to the ETC Group (the Erosion, Technology and Concentration organization based in Canada that tracks emerging technologies), Ecover is the only company that has publicly confirmed the use of synthetic biology to create an ingredient found in a specific product, its Ecover Natural Laundry Liquid.

Ecover buys the algal oil from Solazyme, which used to describe itself as a synthetic biology company but has taken the term off its website.

“We use both natural strains, classic breeding, and strain selection, along with the tools of modern biotechnology, to produce a wide variety of oils and ingredients,” Genet Garamendi, a spokeswoman for Solazyme, wrote in an email.

Solazyme describes the organism that produces the oil as “an optimized strain” of single-cell algae “that have been in existence longer than we have.”

Solazyme pointed to the environmental benefits of its processes and noted that environmental organizations like the World Wildlife Fund support its work.

“We use molecular biology and standard industrial fermentation to produce renewable, sustainable algal oils that help alleviate pressures on the fragile ecosystems around the Equator that are frequently subject to deforestation and habitat destruction,” Jill Kauffman Johnson, the company’s director of sustainability, wrote in an email.

Other environmental and consumer groups, however, want Ecover to note the use of synthetic biology in the new oil it is using so that consumers know what they are buying.

They acknowledge that the new oil — in Ecover’s detergent — does not contain genetically engineered ingredients in the conventional meaning of the term. Rather, the organism producing the oil has been genetically altered.

But they contend that calling products that contain such ingredients “natural,” an obvious selling point for companies, gives a false impression.

“This is not what consumers think of when they see the word natural on a label,” said Michael Hansen, senior scientist at Consumers Union.

Domen of Ecover said there had been a big internal debate about use of the algal oil but that the environmental benefits ultimately outweighed concerns over any negative consumer reaction.

The oil is produced by altered algae grown in a bioreactor, Domen said, and fed with sugar cane. The algae is then harvested and pressed to release the oil, he said.

Domen said that Method, a popular line of household products that Ecover bought in 2012, also is considering using ingredients generated through synthetic biology processes.

He referred questions about how Solazyme disposes of the remains of the algae once the oil is extracted to Solazyme. The company responded: “Resulting biomass is completely inert and can be used in a number of applications that are beneficial to reducing greenhouse gases.”

Ecover said it was working with Friends of the Earth, ETC and other groups to address concerns about labeling its detergent.

“We’re currently still looking into that, specifically, on the labeling, how we can best communicate this,” Domen said. “We definitely want to provide all the information necessary.”